Preheat the oven to 350°F. Line two muffins with cupcake liners.
Mix all of the dry ingredients on slow speed to blend. Add the soft butter and mix until evenly crumbly, like fine damp sand. It may form a paste, depending on the temperature of the butter, how much it's mixed, and granulation of the sugar used.
Add the egg whites one at a time, then the whole egg, beating well after each addition to begin building the structure of the cake. Scrape down the sides and bottom of the bowl after each addition.
In a small bowl, whisk the yogurt with the vanilla and almond extracts. Add this mixture, 1/3 at a time, to the batter. Beat 1 to 2 minutes after each addition, until fluffy. Be sure to scrape down the sides and bottom of the bowl.
Pour the batter into the muffin tins. Using balled-up tinfoilm insert one ball between the muffin tin and the cupcake liner after it's been filled with batter. Repeat with remaining cupcakes.
Bake for 20 to 25 minutes. A toothpick or cake tester inserted into the center will come out clean when done. Remove from the oven and allow to cool for 15 minutes in the pan.