Preheat the oven to 350. Butter or spray a 9 inch springform pan.
Prepare the streusel: Stir together the flour, salt and brown sugar. Add the butter, and using your hands or a pastry cutter, cut the butter into the flour mixture until the butter is the size of peas. Stir in the lemon zest, almonds and almond extract. Set this mixture in the fridge while you prepare the cake.
For the cake: In a medium bowl, whisk the flour, baking powder and salt.
In a large bowl, beat the butter and sugar for several minutes, until light and creamy.
Add the eggs and beat until combined. Add the sour cream, lemon curd, lemon zest and almond extract and beat until combined. Scrape the sides of the bowl as necessary.
Add the dry ingredients and stir until just combined, being careful not to over mix.
Pour the batter into prepared pan (it will be thick), and spread it out evenly. Sprinkle the streusel evenly over the top of the batter. I like to pinch some of the streusel between my fingers to help it "clump" together, as I'm scattering it on top of the cake.
Bake for 35-45 minutes, until a toothpick inserted into the center comes out clean. Begin checking the cake at 35 minutes, you don't want to over bake it. Cool the cake completely on a rack and then top with the glaze.
For the glaze: Stir the lemon juice and powdered sugar together until smooth. Drizzle over the top of the cake.