Source: Cooking Weekends
Moist Yellow Cupcakes with Browned Butter Frosting
The cupcakes do seem moister to me, and they aren't as oily as those at Whole Foods - however, they also don't keep for a week and are best eaten within a day or two.
1 cup unsalted butter, (half of this amount will be used in the frosting)
1/3 cup canola oil
3/4 cup sugar
1/2 cup buttermilk
2 large eggs
1 tbsp vanilla extract
1 tsp baking powder
1/2 tsp baking soda
pinch of salt
1 cup cake flour
1/2 cup unbleached flour
Preheat oven to 350°F. Line a standard 12 muffin tin with baking papers.
Melt the butter in a saucepan and cook until lightly browned. Remove from heat and allow to cool.
Pour 1/2 cup butter into a bowl, reserving the other half for the frosting. Add the canola oil, sugar and buttermilk, then whisk them until well combined. Whisk in one egg at a time.
Whisk in the vanilla extract, baking powder, baking soda and salt. Whisk in the flours until they are well combined.
Spoon/pour the batter, dividing equally among the 12 lined baking cups. Bake for about 13-16 minutes or until done. Be careful not to over-bake them; I began to watch them closely after 13 minutes.
Remove from the oven and cool.
1/2 cup browned butter, (the reserved amount from earlier)
1/4 cup sour cream
1 tsp vanilla extract
2 - 2 1/2 cups icing sugar
Beat the butter, sour cream, vanilla extract and 2 cups icing sugar, together in a bowl. Keep adding more icing sugar until the frosting has the right consistency. Decorate the cooled cupcakes.