Lemon Coffee Cake (Meyer)

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.

Streusel:
1¾ cups all-purpose flour, unbleached
¾ cup light-brown raw sugar, packed
1 tsp. coarse sea salt
6 oz (¾ cup) unsalted butter, cold

Cake:
5 Meyer lemons, cut into paper-thin slices, ends discarded
2 cups all-purpose flour, unbleached
1 tsp. baking powder
1 tsp. baking soda
1½ tsp. coarse sea salt
4 oz (½ cup) unsalted butter, room temperature + more for pan
1 cup raw sugar
3 Tbsp. Meyer lemon zest, finely grated (from 4-5 lemons)
2 large eggs
1 tsp. pure vanilla extract
1 cup sour cream

Glaze:
1 cup confectioners' sugar
3-4 Tbsp. Meyer lemon juice, freshly squeezed

For 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.

For the Cake:
In a large skillet of simmering water, cook lemon slices 1 minute. Drain and repeat. Arrange lemon slices in a single layer on a parchment-lined baking sheet.

Preheat oven to 350°F (180°C/160°C fan, Gas Mark 4). Butter a 9" angel food cake pan.

Sift together flour, baking powder, baking soda, and salt. In a mixer fitted with the paddle attachment, beat together butter, granulated sugar, and lemon zest on medium speed in a large bowl until light and fluffy, about 2 minutes. Beat in eggs, one at a time, then vanilla. Reduce speed to low. Beat in flour mixture in three additions, alternating with sour cream, beginning and ending with flour mixture and beating until combined after each addition.

Spoon half of batter evenly into pan. Arrange half of lemon slices in a single layer over batter. Spread remaining batter evenly over top. Cover with remaining lemon slices in a single layer. Sprinkle chilled streusel evenly over batter.

Bake until cake is golden brown and a tester inserted in center comes out clean, about 55 minutes. Transfer pan to a wire rack set over a baking sheet; let cool in pan 15 minutes. Run a knife around edges of pan and remove outer ring. Let cool on rack 15 minutes more. Run a knife around center tube. Slide two wide spatulas between bottom of cake and pan, and lift cake to remove from center tube. Let cool completely on rack.

For the Glaze:
Just before serving, stir together confectioners' sugar and lemon juice in a medium bowl. Drizzle over cooled cake, letting excess drip down sides. Let glaze set before slicing, about 5 minutes.

Makes 12 servings.

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.