Streuselkuchen is a German specialty. Traditionally it is made of a yeast dough covered with a sweet crumb topping referred to as streusel. YUM!
large eggs, at room temperature
Make the German yeast dough: Scald the milk in a small saucepan over medium heat. You will see steam rising from the surface of the milk and small bubbles forming around the edges. Remove the pan from heat and let stand until the milk feels warm to your fingertip, about 10 minutes; an instant-read thermometer should register 110-120ºF (43-48ºC). Sprinkle the yeast and 1 teaspoon of the sugar into the milk and stir well. Let stand for about 10 minutes, until the yeast is bubbly and foamy. To make the dough using a stand mixer (which is what I did): combine 2 1/4 cups of the flour with the remaining sugar in the bowl of the mixer and add the butter and lemon zest. Attach the flat beater and mix on low speed for about 3 minutes, until the flour looks mealy. Remove the bowl from the mixer stand, add the yeast and eggs, and stir with a rubber spatula to make a moist, thick dough. Switch to the dough hook and beat on low speed for 1 minute. Increase the speed to medium and beat for 5 minutes, or until the dough becomes sticky and elastic and begins to pull away from the sides of the bowl. Scrape the bowl and the dough hook. To make the dough by hand: stir 2 1/4 cups of flour with the remaining sugar in a large mixing bowl. Add the butter and cut it in with a pastry blender or two knives until the flour looks mealy. Add the lemon zest, then add the yeast and eggs and stir with a wooden spoon to make a moist, thick dough. Beat vigorously for 5-8 minutes until the dough becomes smooth, sticky and elastic. When you pick some of the dough with the spoon, it will be very stretchy. Scrape the bowl and spoon. Sprinkle 1 tablespoon flour over the dough and cover the bowl tightly with plastic wrap. Let the dough rise until doubled in size, 1 hour or more depending in the warmth of your kitchen. Lightly flour your work surface. Dislodge the dough from the bowl with a pastry scraper, scrape it out onto the work surface and turn to coat all surfaces lightly with flour. Divide the dough in half. Shape each half into a ball, cover loosely with a clean kitchen towel and let rest for 10 minutes. The dough is now ready to use. Note: if you are using only half the dough, place the second ball of dough into an airtight container and refrigerate it. The next day, shape and bake it into another Streuselkuchen. Make the streuselkuchen: Butter a 9-inch square baking pan* (do not use cooking spray – the dough must adhere to the pan). Roll the dough on a lightly floured surface to the size of the pan. It will be about ¼ inch thick. Transfer the dough to the pan and pat it onto the bottom and into the corners. Do not make a rim; the dough should be flat. Cover with a kitchen towel. To make the streusel, put the flour, confectioners’ sugar and butter into the work bowl of a food processor (I used my Kitchen Aid mixer with the paddle attachment) fitted with the metal blade. Pulse 5 or 6 times, then let the machine run just until the ingredients begin to form small crumbly masses, about 30 seconds. Do not process beyond the crumb stage. Uncover the dough. Press the crumbs to form clumps the size of large peas, and sprinkle on the top of the dough. Continue making larger lumps of streusel and sprinkling them evenly all over the dough. There will be a generous layer of streusel covering the dough. Cover the Streuselkuchen with a kitchen towel and let stand at room temperature for 20 minutes. Adjust an oven rack to the center position and preheat the oven to 350ºF. Uncover the kuchen and place the pan in the oven. Bake for about 30 minutes, until the kuchen has risen almost to the top of the pan and is golden brown and a toothpick inserted into its center comes out clean. Remove the pan from the oven and immediately sprinkle the top with a generous layer of vanilla confectioners’ sugar. Cool completely on a wire rack. This is at its best when very fresh. Cut into portions with a sharp knife. NOTE: I used a 20cm (8-in) square pan and it worked fine.