1) Preheat the oven to 350°F. Grease a tube pan, or a 9" x 13" pan.
2) To prepare the streusel: Stir together the dry ingredients. Cut in the cold butter, then add the grated rind and pecans.
3) To prepare the cake: Sift together the flour, baking powder, salt, lemon powder (or grated rind), and cinnamon.
4) Beat the butter and lemon oil together until the butter is soft. Add the sugar and beat until light and creamy.
5) Add the eggs one at a time, followed by the sour cream, beating after each addition and scraping down the bowl as needed.
6) Add the dry ingredients, stirring just until incorporated.
7) Spoon the batter into the prepared pan and smooth the top. Sprinkle the streusel evenly over the batter.
8) Bake the cake for 40 to 45 minutes, until a cake tester inserted into the center comes out clean. If you've used a tube pan, allow the cake to cool slightly, then turn it out onto a plate. Using another plate, turn it over again so the streusel is on top. If you've baked the cake in a 9" x 13" pan, serve it right from the pan.
9) To prepare the glaze: Stir the lemon juice and confectioners' sugar together. Drizzle over the cake.
Yield: 16 to 24 servings.