In a bowl, stir together the flour, baking soda and salt.
In the bowl of your electric mixer, beat the butter and sugar together on high speed until creamy, about 3 to 4 minutes. Beat in the egg yolks one at a time. Beat in the extracts and lemon zest until combined.
Beat in half of the flour mixture until just combined. Beat in the greek yogurt. Beat in the remaining dry ingredients until just combined.
In a bowl, beat the egg whites with an electric hand mixer until foamy. Gradually add in the 2 tablespoons of sugar, beating until stiff peaks form. Fold the egg white mixture into the cake batter.
Spread the batter into the greased baking dish. Dollop the lemon curd on top and gently swirl it in with a knife.
Sprinkle the crumb mixture all over the batter. Bake for 40 t0 45 minutes, or until a tester inserted in the center comes out clean. Remove from the oven and sprinkle the top with powdered sugar.