3 tablespoons butter at room temperature
1 tablespoon ground cinnamon
3 tablespoons all-purpose flour
¾ cup packed brown sugar
¾ cup chopped walnuts or pecans
½ cup butter at room temperature
1 cup granulated sugar
2 large eggs at room temperature
1 teaspoon baking powder
1 teaspoon baking soda
¾ teaspoon salt
1 teaspoon vanilla extract
2 cups all-purpose flour
1 cup buttermilk at room temperature
1. Butter 12x7.5-inch glass baking pan and heat oven to 325°F.
2. In medium-sized bowl, prepare streusel by blending cinnamon and salt into softened butter.
3. Stir in flour, then brown sugar, and then nuts. Use hands if desired.
4. In large bowl, prepare cake batter by creaming butter. Then add granulated sugar and beat until light and fluffy.
5. Beat in eggs, one at a time, scraping down bowl as needed.
6. Beat in baking powder, baking soda, salt, and vanilla.
7. Hand-stir flour mixture into creamed mixture in three batches, alternating with half of buttermilk. Do not over-stir.
8. Spread half of batter in prepared pan. Evenly top with half of streusel. Carefully spread remaining batter over strewn streusel. Then sprinkle remaining streusel on top.
9. Bake for about 45 minutes or until cake is set and a toothpick inserted in the center comes out clean.
10. Cool cake on a rack for 15 to 20 minutes before cutting and serving.