Preheat oven to 350°F (177°C). Line a 12-count muffin pan with 12 cupcake liners. Set aside.

In a large bowl, mix flour, baking powder, baking soda, and salt together. Set aside. In a medium microwave-safe bowl, melt butter in the microwave. Whisk in the sugar; the mixture will be gritty. Whisk in yogurt, milk, vanilla extract, and almond extract until combined. Slowly mix dry ingredients into the wet ingredients until no lumps remain. Batter will be thick. Do not over-mix. Set aside.

Using a whisk, a handheld mixer, or a stand mixer fitted with a whisk attachment, beat the egg whites until until thick and foamy, about 3 minutes. With a rubber spatula, fold the whipped egg whites into the cupcake batter. The batter will be smooth, velvety, and slightly thick. Divide batter among 12 cupcake liners and bake for 20 minutes or until a toothpick inserted in the center comes out clean. Allow cupcakes to cool completely before frosting.

While the cupcakes cool, melt the white chocolate for the frosting: Place chopped white chocolate in a microwave-safe bowl (I usually use a glass liquid measuring cup), and microwave in 20-second increments, stirring after every 20 seconds until completely smooth. Set it aside to cool at room temperature for 20 minutes. (Be sure the melted white chocolate has cooled for 20 minutes, so it’s still melted but not scorching hot, which would melt the butter.)

In a medium bowl using a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed for 1 minute. Switch the mixer to low speed and slowly add the confectioners’ sugar. Stir the cooled white chocolate so that it is smooth, and then add it to the butter/sugar mixture. Switch the mixer to medium speed and beat for 2 minutes until combined and creamy. Add the cream, vanilla extract, and salt. Beat for 1 minute until combined. Taste. Add 1 more Tablespoon of heavy cream/milk if needed to thin out, if desired. Add another pinch of salt if frosting is too sweet.

Frost the cooled cupcakes. I used a Wilton 1M swirl piping tip to pipe the frosting.