Every year I look forward to the flood of local and regional blueberries that arrives with the height of summer here in the Midwest. I eat them every morning with yogurt (and peaches)...and I tuck them into desserts of all kinds. A few years ago when I decided to teach a class called "High Summer at the Farmers' Market", I knew I had to include a dessert made with blueberries. Rather than my usual...cake, tart, crisp, etc.....I decided to pair them with lime in a cool and refreshing cheesecake.
You might not think of putting lime together with blueberry. At least, I didn't until I was introduced to the combination by my friend Bonnie. She has been enamored with the combination since first tasting it years ago in a lime custard parfait with blueberry sauce. The first time I tasted the combination was when I was assisting Bonnie with a muffin class. She topped her blueberry muffins with a light crunchy streusel that was loaded with lime zest rather than the more typical lemon zest. I was struck by how well the lime complimented the blueberry...and have remembered it ever since.
As it happens, lime season—both Persian/Bearss and Mexican/Key—intersects blueberry season (making their pairing all the more appropriate). Because they are available year round, I tend to forget that limes have a season. But they do....from early summer and on into fall, they are at their peak. I have chosen to make my cheesecake with the more unusual Key lime...I think the spicy/aromatic quality of these little guys is especially nice with the blueberries...but I imagine this cheesecake would be pretty fine with the more widely available (and easier to juice) Persian limes.
If you do choose to use Key limes (and I hope you will) the best way I have found to extract their juice is as follows: Instead of cutting the limes in half, just shave off enough of one end to expose the flesh. Working over a bowl, slide a fork into the lime and wiggle it from side to side as you squeeze the lime with your other hand. If you can, try to rotate the fork a little bit as you work it from side to side—this will help to tear up the membranes a bit and release more juice. I won't lie...if you are lucky, you will get a tablespoon of juice from each lime. You might only get a half tablespoon. Because the yield is so meager, I also squeeze out the very small amount juice in the little "cap" I sliced off of the end...every little bit helps. If you want to use the zest of the limes, scrub them (they are almost always waxed) and zest them before juicing them.
As for the cheesecake itself, the recipe is fairly basic. It is the method that is important when it comes to getting a beautiful, creamy result. First, make sure that your cream cheese has had time to come to room temperature so that it will be soft. Resist the temptation to beat the ingredients at a high speed. This will result in over-beating which will cause the cake to soufflé up in the oven and collapse in the center as it cools. When mixed at a lower speed, the final cake will be level and uniform in texture. As you begin to mix, the cream cheese will have a tendency to get hung up in the paddle. Simply stop the machine and scrape the paddle and the sides.
Continue to do this until the cream cheese is smooth. Then, begin to add each of the ingredients. First the sugar...
then the flour/salt...then the lime juice with the vanilla...
and finally the eggs. After each of these groups of ingredients have been added, it is important to make sure that the bowl and paddle are well scraped and that the batter is completely smooth. With each successive addition, the batter becomes thinner and any thick-ish lumps that have not been smoothed out will remain (which will result in and uneven texture in the final cake).
Earlier this week when I taught this class, someone asked me why I didn't include any lime zest in the cheesecake. This is an excellent question, because citrus zest adds a great deal of flavor. You can of course include some lime zest in the cake if you like. I don't because I don't want the bits of texture from the zest in the cake. Instead, I include some zest in the blueberry compote.
The blueberry compote is a recipe that I adapted from Rose Levy Beranbaum's The Pie & Pastry Bible. It makes a perfect topping for a cheesecake: thick, with berries that are whole and intact. The original recipe calls for lemon juice and lemon zest. I of course have used lime juice and the aforementioned lime zest.
I love this cheesecake. It is super creamy, wonderfully tart & refreshing and loaded with summer flavor. It even won a little informal cheesecake "throwdown" (you can read about it at Katrina's blog Baking and Boys). And, in the midst of a class filled with what I think are exceptional summer recipes (Pasta with Summer Squash & Sweet Corn, Chicken Salad with Cantaloupe, Feta & Mint, and Pizza with Roasted Pepper & Potatoes), this recipe is always a favorite.
Key Lime Cheesecake Squares
with Blueberry Compote
Graham Cracker Crust:
5 oz. graham crackers, finely ground (to make a scant 1 1/2 cups crumbs)
3 T. granulated sugar
2 oz. (4 T.) unsalted butter, melted
Line a 9-inch square baking pan with 2 criss-crossed sheets of foil, leaving an overhang. Butter or spray the pan. Combine the crust ingredients until homogenous and press into the pan in a compact even layer. Bake in a pre-heated 350° oven until just beginning to brown—8 to 10 minutes. Cool.
Key Lime Filling:
3 8-oz. packages cream cheese, room temperature
1 c. sugar
2 T. all-purpose flour, sifted
1/4 t. salt
1/3 c. strained key lime juice
3 eggs, at room temperature and lightly beaten
1/2 t. vanilla
Briefly beat cream cheese to break up. Beat in the sugar until smooth; scrape the sides. Beat in the flour & salt; scrape the sides. Add the lime juice and vanilla and beat in. Scrape the sides. Beat in the eggs in two or three additions, just until smooth and fully incorporated. Scrape the batter into the prepared pan.
Place the pan on a half-sheet pan and place on the oven rack in a pre-heated 325° oven. Pour in hot water to come up at least half as high as the batter in the pan. Bake until just set--about 40 to 45 minutes. Cool to room temperature (about 2 hours). Chill, uncovered, until cold (at least 2 hours, but cheesecake may be baked a day or two ahead).
To portion, lift the cold cake out of the pan using the overhang of foil. Cut the cake using a sharp, thin knife dipped in hot water (and wiped dry) in between cuts. First, trim the edges. Then cut into three 2 3/4-inch wide strips. Cut each strip evenly into 3, 4 or 5 pieces depending on whether you want 9, 12 or 15 portions. You may also cut 18 buffet-sized portions by cutting 9 squares and then cutting each square in half on the diagonal.
Serve topped with a spoonful of blueberry compote.
14 oz. blueberries (about 2 3/4 c.)
75 g. sugar (6 T.)
1 T. Key (or Persian) lime juice
zest of 1 Persian lime or 3 or 4 Key limes
1/2 oz. cornstarch (2 T.)
Combine the berries with the sugar, lime juice and zest in a wide, shallow saucepan. Let macerate for 30 minutes. Dissolve the cornstarch in a small amount of cold water and add to the berries. Bring to a boil, stirring gently with a heat-proof rubber spatula. Let boil until the juices are clear and very thick--about a minute. Empty into a bowl and cool without stirring. Chill. Makes a generous 2 cups.
(Compote/topping adapted from The Pie and Pastry Bible, by Rose Levy Beranbaum)