Vapor Baker: Apricot Almond Chai Cheesecake w/ Black-Tea Biscuit Crust (Baked)

[ Equipment: oven or slow cooker with temperature control. For more information about the terminology in this recipe, see Low Temperature Baking: A Journey of 3 Paths. ]

Revised Jan. 1, 2011.

This rich tasting (yet low fat), gooey texture, 7-inch cheesecake combines the smooth silkiness of cream cheese with the tang of active-culture yogurt, dotted with chunks of apricots, on top of a crunchy, smokey crust of black tea, almonds and molasses. It's baked at 3 temperatures: 250°F/121°C for the crust alone, 220°F/104°C for the first layer of filling and 200°F/93°C for the second layer of filling. The thin uncooked batter cannot hold the apricot bits in suspension, so a barely set bottom layer provides a platform for the apricots. Once the top layer sets, no seam can be discerned between them. Because it's an LTB cheesecake, it never cracks (at least it's never cracked when I made it).

Cheesecake ingredients purchased in large quantities for testing recipes can be expensive, so I postponed thinking about a LTB cheesecake for a long time. I began the planning when a local market had a 50%-off sale on McCormick bottled spices. I stocked up like crazy. All the bottles I purchased were discounted except one labeled Chai Spice Blend, for which I paid full price. Chai tea is one of my favorite beverages.

Coincidentally, another market near me was almost giving away American Neufchâtel cheese (a.k.a. low-fat cream cheese) at 75% off the regular price. I purchased several pounds of Neufchâtel cheese. The neural gears in my brain put these ingredients together: Neufchâtel cheese plus chai spices equals a chai-spiced cheesecake! Like the tea that inspired it, this cheesecake would be light, aromatic and refreshingly sweet.

Between sour cream and yogurt to dilute the cream cheese into a batter for the filling, I went with a low-fat active-culture vanilla yogurt as a more balanced pairing with the finer flavor Neufchâtel cheese. A low-fat plain yogurt will work too by increasing the amount of sugar to 3/8 cup and mixing in 1/2 teaspoon of vanilla extract. Low-fat homemade yogurts (1% or 2% milk) tend to be softer and thinner, but could be drained in a cheesecloth to thicken or if fermented for over 12 hours, will thicken to the same consistency as a firm commercial yogurt with a very strong tang.

As an alternative for the bottled McCormick Chai Spice Blend, McCormick's website has a recipe that consists of 1/2 teaspoon each cardamom, cinnamon and ground gloves plus a pinch of white pepper. It's definitely not the same as their bottled Chai Spice Blend. The label on the bottle just says: "spices including ginger, cinnamon and sugar", so there are one or more secret ingredients. If I were going to try and create a substitute, I would mix cardmom, cinnamon, ground cloves, ginger and white pepper. eHow has a chai spice recipe with all these ingredients.

To add a little complexity, I mixed almond and apricot flavors into the filling and crust. The chai spices played well with the muted fruitiness of the apricots, and almonds were a natural fit with apricots (apricot pits are also called bitter almonds). At one time, I thought of layering ground almonds into the filling, but wasn't sure that the abrupt change in texture inside the creamy filling would be welcome in a cheesecake. The chopped apricots varied the texture without grit or hard edges.

Normally, fillings with fruit or nut add-ins must be highly viscous (the cheese diluted with eggs only) to hold them in suspension or the add-ins will sink to the bottom. The 2-layer assemblage in this recipe simulates that capacity in a thin batter and may actually speed up the baking time, because the center of the filling has been exposed to more heat than if it had been all poured in a single layer. The one caveat is the first layer should be filled as soon as it can support the apricot bits. The longer the first layer bakes, the more likely it will overbake before the second layer is done.

I found no-crust and ready-made-crust cheesecake recipes online that bake below 200°F - well into the range of sous vide cooking, so LTB was not issue for the filling. The main challenge in this recipe was the crust, what style and whether to bake it separately or as a single unit with the filling. I wanted to try something other than the traditional crushed graham cracker crust. The first cheesecakes I made had a cake-like crust, based on a Pennsylvania-Dutch cheesecake called a smearcase cake. However, I came to realize that I like the contrast in textures of the smooth cream cheese against crunchy graham cracker crusts.

I developed my own crust based on a shortbread cookie dough fortified with almond meal, chai spices, specks of powdered black tea and molasses. There very little mixing in preparing the dough (the ingredients gently combined like in a pie crust) for a tender yet crunchy texture. The powdered black tea thematically complements the chai spices and gives the biscuit crust a hint of smokiness. (Powdered green tea in previous crusts colored the dough, but the delicate green tea flavors receded against the other robust and pungent ingredients.) To make black tea powder, I finely ground Twinings English Breakfast Tea in a coffee grinder. The Twinings is a blend of Kenyan and Assam black teas, but just about any black tea suitable in a chai tea should be a good substitute.

In the final analysis, it's the molasses in the dough that brings in an echo of the traditional graham crackers. I hadn't intended it at all - molasses is a complementary sweetener in chai tea. Then I looked up graham cracker recipes, and there they were: molasses and cinnamon (also a component of the chai spices) as the key flavor agents. Well, the benefit of making a crust from scratch is choosing the ingredients and baking it the LTB way. My local markets don't sell graham crackers made with almond meal, black tea and chai spices (and probably no place else does either).

For this recipe, the crust was prebaked and then coated with an almond butter to waterproof it against the liquid filling, so that remained crunchy when served. In the pictures, I substituted a natural peanut butter for the almond butter, but the peanut flavor asserted itself a little too much. A mild peanut butter blend (I saw one containing flax meal and flax oil) might work too.

When the filling bakes, the crust must not overbake, so the trick is to finish the crust's prebake quickly. The crust in the picture was baked for the full 40 minutes. Although dark (from the molasses and black tea) and crunchy, it didn't taste burned. For a softer crust, I'd try baking it for around 30 minutes, when the biscuit center could still be a little bit fragile. It should firm up as it cools.

After the crust prebake, the oven is cooled to 220°F/104°C to bake the first layer of the filling and then cooled again to 200°F/93°C for the second layer. The lower temperatures are meant to protect both the filling and the crust from overbaking, so that the filling comes out moist and gooey, the modern standard for a good cheesecake. I actually like a very firm cheesecake, but everyone else online seems to prefer a so-soft-it-could-collapse-on-the-plate texture. Well, so be it. In my defense, I must say that a firm (if overbaked) cheesecake can be easily cut, wrapped and stored in the fridge. These super-soft cheesecakes fall apart if tightly wrapped in plastic, unless they're frozen first.

Makes 8 or 12 servings
- 262 calories per serving (8 servings) or 175 calories per serving (12 servings)
- Oven temperatures: 250°F/121°C, 220°F/104°C, 200°F/93°C

Crust:

3/8 cup all-purpose flour
1/8 cup almond meal
1/4 cup granulated sugar
1/8 teaspoon baking powder
1/8 teaspoon baking soda
1/2 teaspoon black tea powder (see text)
1 teaspoon McCormick chai spice blend (see text)
1/4 teaspoon ground flax seed or flax meal (optional binder)
1-1/2 tablespoon butter
2 tablespoons unsulfured molasses
2 tablespoons almond butter or other nut butter (see text)

Filling:

8 oz. American Neufchâtel cheese (low-fat cream cheese)
1 cup low-fat active-culture vanilla yogurt (see text)
1/4 cup sugar
1 tablespoon all-purpose flour (optional)
pinch of salt
2 teaspoons McCormick chai spice blend (see text)
2 large eggs, beaten
6 to 8 dried apricots

Crust Method:

1. Into a medium bowl, sift the flour and almond meal. Then whisk in the sugar until well combined. As an alternative to the sifting and mixing, I will put the flour, almond meal and sugar in the bowl and rub it between my hands to combine them and eliminate any lumps.

2. Add chai spices, baking powder, baking soda and ground flax seeds.

3. Cut butter into small cubes and add to flour mixture. Cut in the butter with a fork or rub the butter and flour between hands to get an evenly crumbly texture. With the hands method, work fast so that the butter doesn't melt and lump up the flour.

4. Add the molasses 1/2 tablespoon at a time and toss-press with the flour mixture until evenly coated and it forms a dough. The technique is like that for making a pie crust.

5. Grease a 7-inch springform pan or cake pan with removable bottom. Cut out a 7-inch diameter circle from wax paper or parchment paper and place in bottom of pan. Grease the top of the paper.

6. Break off pieces of the dough, and pat them evenly onto bottom of pan.

7. Bake crust at 250°F/121°C for 30 to 40 minutes, until the edges are a light brown. Remove from the oven and let the crust cool. Check that the crust is firm and the surface is dry before proceeding to next step.

6. Spread the almond butter or other nut butter in a thin layer over the top of the crust.

Filling Method:

1. In a small dish, cover the dried apricots in boiling water and allow to soak for at least 1 hour. Drain and finely chop the apricots. Set aside.

2. In a bowl, mash cream cheese and yogurt with fork until well blended.

The reason for mixing with a fork in steps 1 to 3 (and not an electric mixer) is to minimize the amount of air whipped into the batter. If the batter has too much air, the cheesecake could rise during baking and collapse as it cools, leaving a depression in the center. An electric mixer is applied briefly in step 4 to break down any lumps.

3. Mix in the sugar.

4. Mix in the flour, salt, chai spices and almond extract. Now is a good time to taste the batter and adjust flavorings.

5. Mix in the beaten eggs.

6. Briefly puree the batter with an immersion blender or electric mixer to break up any lumps.

7. Heat the oven to 220°F/104°C. Place the pan with the biscuit crust back in the oven.

8. Pour 1/2 of the batter (about 1-1/4 cup) into pan and bake for 50 to 60 minutes or until the filling has set just solid enough to support the weight of the apricot bits. Test the firmness by dropping a piece of the chopped apricot onto the filling. If it floats in the filling, proceed to the next step.

9. Sprinkle the chopped apricots evenly over the filling.

10. Pour remainder of batter into the pan. Reduce the oven temperature to 200°F/93°C and continue baking for another 60 to 80 minutes or until cheesecake is firm when the pan is shaken EXCEPT that the center (about 3-inch diameter) wobbles a little.