Meyer Lemon Coffee Cake

From Martha Stewart

Layers of thinly sliced Meyer lemons lend a mellow complexity to this otherwise classic coffee cake. Thought to be a cross of a lemon and a mandarin, the fruit has an orange cast, a thin rind, and a heavily perfumed flesh that's valued by chefs.

Serves 10 to 12

Ingredients
For the Streusel
        1 3/4 cups all-purpose flour
        3/4 cup packed light-brown sugar
        1 teaspoon coarse salt
        6 ounces ( 3/4 cup) cold unsalted butter
   
For the Cake
        5 Meyer lemons, cut into paper-thin slices, ends discarded
        2 cups all-purpose flour
        1 teaspoon baking powder
        1 teaspoon baking soda
        1 1/2 teaspoons coarse salt
        4oz (1/2 cup) unsalted butter, room temperature, plus more for pan
        1 cup granulated sugar
        3 tablespoons finely grated Meyer lemon zest (from 4 to 5 lemons)
        2 large eggs
        1 teaspoon pure vanilla extract
        1 cup sour cream
   
For the Glaze
        1 cup confectioners' sugar
        3 to 4 tablespoons Meyer lemon juice

Method
Make the streusel: Mix together flour, brown sugar, and salt. Using a pastry cutter or your fingers, cut butter into the flour mixture until small to medium clumps form. Cover, and refrigerate until ready to use (up to 3 days).
   
Make the cake: Cook lemon slices in a medium saucepan of simmering water for 1 minute. Drain, and repeat. Arrange lemon slices in a single layer on a parchment-lined baking sheet.
   
Preheat oven to 350°F. Butter a 9-inch angel food cake pan. Sift together flour, baking powder, baking soda, and salt. Beat butter, granulated sugar, and lemon zest with a mixer on medium speed in a large bowl until light and fluffy, about 2 minutes. With the mixer running, add eggs, 1 at a time, then the vanilla. Reduce speed to low. Add the flour mixture in 3 additions, alternating with sour cream.
   
Spoon 1/2 of the batter evenly into cake pan. Arrange 1/2 of the lemon slices in a single layer over the batter. Spread remaining batter evenly over the top. Cover with the remaining lemon slices in a single layer. Sprinkle the chilled streusel evenly over the batter.
   
Bake until cake is golden brown and a tester inserted in the center comes out clean, about 55 minutes. Transfer pan to a wire rack set over a baking sheet, and let cool in pan for 15 minutes. Run a knife around the edges of the pan, and remove outer ring. Let cool on rack for 15 minutes. Run a knife around the center tube. Slide 2 wide spatulas between the bottom of the cake and the pan, and lift cake to remove from the center tube. Let cool completely on rack.
   
Make the glaze: Just before serving, stir together confectioners' sugar and lemon juice in a medium bowl. Drizzle over cooled cake, letting excess drip down the sides. Let glaze set before slicing, about 5 minutes.

Cook's Note
Mildly acidic Meyer lemons are available from late fall through early spring. For the rind to soften and sweeten sufficiently during baking or roasting, slice the lemon to near-transparent thinness. A mandoline, a handheld slicer, or a sharp knife and a steady hand will do the trick.

Variations
Martha has also prepared the lemon glaze with just two tablespoons of Meyer lemon juice.