German Blueberry Streusel Cake

To make the streusel, in a stand mixer with the paddle attachment, mix the flour, both sugars and salt on medium-low until well combined and any lumps of brown sugar have broken apart, 1 to 2 minutes. With the mixer on low, add the butter 1 piece at a time, then mix on medium-low until fully incorporated and the mixture resembles damp sand, 1 to 2 minutes. Transfer the streusel to a medium bowl, cover and refrigerate. Wipe the mixer bowl and the paddle attachment.

To make the dough, in a 2-cup liquid measuring cup or small bowl, whisk the milk, whole egg and yolk, lemon zest and yeast. In the mixer bowl using the paddle attachment, mix the flour, sugar, salt and cinnamon on medium-low until combined, about 30 seconds. With the mixer running, slowly add the milk-egg mixture; mix until the dry ingredients are evenly moistened, about 30 seconds. Increase to medium and beat until a sticky, webby mixture forms, about 3 minutes.

Scrape the bowl. With the mixer running on medium-low, add the butter 1 piece at a time, mixing for about 15 seconds before adding the next. When all the butter has been added, scrape the bowl and mix on medium until a very sticky, elastic, batter-like dough forms, 2 to 3 minutes. Remove the paddle attachment and scrape off the dough that clings, allowing it to fall back into the bowl. Scrape the sides of the bowl and gather the dough in the center. Cover and let rise at room temperature for 1½ hours; the dough will not double.

Meanwhile, butter a 9-by-13-inch baking pan or glass baking dish, then line it with a 16-inch sheet of foil so the ends overhang the long sides of the pan. Butter the foil.

After the dough has risen for 1½ hours, scrape it into the center of the prepared pan. Lightly dust the top with flour and flour your hands. Starting from the center and using outstretched hands, firmly press the dough into an even layer to the edges and into the corners of the pan. Re-flour your hands as needed and press the dough firmly to remove as many air bubbles as possible. Do not pull or stretch the dough, which may cause it to tear, and make sure the edges are not thicker than the center. Cover with plastic wrap, drape a kitchen towel over the pan and refrigerate for 8 to 24 hours.

When you are ready to bake, remove the dough and streusel from the refrigerator and let stand at room temperature for about 45 minutes; the dough will rise only slightly. About 30 minutes into rising, heat the oven to 350°F with a rack in the lower-middle position.

Uncover the pan. Scatter the blueberries on the dough in a single layer. Scoop up a big handful of streusel, firmly squeeze in your hand it until it forms a cohesive clump, then crumble and break the clump into bits no larger than the size of a shelled peanut, scattering them onto the berry-topped dough; aim for a mix of fine crumbles and larger pebbly pieces. Continue adding the remaining streusel in this way, evenly covering the surface.

Bake until the streusel is light golden brown, 30 to 35 minutes. Cool in the pan on a wire rack for about 30 minutes. Run a thin-bladed knife between the cake and pan along the short edges of the pan. Using the foil overhang as handles, lift the cake out of the pan and set it on the rack. Cool completely before serving.

German Cherry Streusel Cake: Follow the recipe to make the streusel and dough, allow the dough to rise, pat it into the prepared baking pan and refrigerate as directed. After removing the dough from the refrigerator, cut 225 grams (1½ cups) pitted fresh or thawed frozen cherries in half if medium in size or into quarters if large, then pat dry to wick away excess moisture, especially if using frozen. Continue with the recipe to heat the oven and top the dough, using the cherries in place of the blueberries. Bake and remove from the pan as directed.