2 (1 ounce) squares unsalted butter
1 1/3 cups all-purpose flour
1 cup brown sugar
1 cup white sugar
1 teaspoon baking powder
1/2 teaspoon salt
1 egg
1 cup milk
Preheat oven to 400 degrees F (200 degrees C). Grease 12 muffin cups or line with paper muffin liners.
In a large bowl, cream together the 1/3 cup butter and brown sugar until light and fluffy. Beat in the white sugar and salt. Beat in the flour one cup at a time, then stir in the egg and milk. Fold in the egg mixture just until incorporated. Pour dough into prepared muffin prepared liners.
Bake in preheated oven for 25 to 35 minutes, or until a toothpick inserted into center of a muffin comes out clean. Serve warm.