- 4 tablespoons (½ stick) cold unsalted butter, cut into bits
- 1/3 cup unbleached all-purpose flour
- ½ cup firmly packed light brown sugar
- 1 teaspoon ground cinnamon
- 1 cup (4 ounces) pecan halves
- 4 tablespoons (½ stick) unsalted butter at room temperature
- ½ cup firmly packed light brown sugar
- ½ cup granulated sugar
- 2 large eggs
- 1 teaspoon vanilla extract
- 2 cups unbleached all-purpose flour
- 1 teaspoon baking powder
- 1 teaspoon baking soda
- ¼ teaspoon salt
- 1 cup buttermilk or low-fat plain yogurt
- Preheat the oven to 350°F. Butter a 9-inch springform pan and line the bottom with a round of parchment paper.
- To make the streusel topping: In a medium bowl or a food processor, combine the butter, flour, brown sugar, and cinnamon. Cut the butter in with your fingers or process until the mixture forms coarse crumbs. Stir in the nuts and set aside.
- In a large bowl, cream the butter and sugars with a wooden spoon or an electric mixer until light and fluffy. Add the eggs and vanilla and beat until smooth. In a medium bowl, combine the flour, baking powder, baking soda, and salt. Stir to blend. Add to the creamed mixture alternately with the buttermilk or yogurt in 2 increments. Beat until smooth. Spread evenly in the prepared pan and sprinkle evenly with the topping.
- Bake for 30 to 35 minutes, or until the cake is golden brown and a cake tester inserted in the center comes out clean. Let cool in the pan on a wire rack for 10 minutes, then remove the pan sides and let cool completely. Cut the cake into wedges to serve.