Preheat oven to 350 and line two 12-cup muffin tins (this recipe makes about 24 cupcakes).
In a large bowl, cream butter until light and fluffy, about 1-2 minutes. Gradually add in sugar, 1/2 cup at a time, beating until well combined.
In a separate bowl, sift together flour, cornstarch, baking powder, and salt. Set aside.
In a small bowl, mix together milk, vanilla extract, almond extract, and Greek yogurt.
Alternately add dry and wet ingredients into the creamed butter mixture, beginning and ending with the dry ingredients. Stir until just combined.
Beat egg white until they form stiff peaks. Gently fold egg whites into the cake batter.
Pour batter into lined muffin pans, and bake for 16-17 minutes, or until a cake tester comes out clean.
For the frosting, beat butter until light and fluffy. Add in powdered sugar, a cup at a time starting with only 3 cups. Add in heavy cream, vanilla extract, almond extract, and a pinch of salt. Beat until light and fluffy, about a minute.
If the frosting is too thin, add in the other cup of powdered sugar, 1/2 a cup at a time. If it's too thick, add in more heavy cream, a Tbsp at a time.
Once the cupcakes have cooled, pipe the frosting on.
Enjoy!