1 cup (2 sticks) unsalted butter, at room temperature
1 cup vanilla sugar (see Cook's Note)
3 large eggs
1 1/2 teaspoons pure vanilla extract
2 1/4 cups all-purpose flour
1/2 teaspoon nutmeg
1 teaspoon baking soda
1/2 teaspoon fine salt
1/2 cup sour cream
1 large Gala or other baking apple, peeled, cored, and finely chopped (about 1 cup)
1/2 cup apple butter
8 ounces cream cheese, at room temperature
1 stick unsalted butter, at room temperature
1 1/2 teaspoons vanilla extract or vanilla paste
1 teaspoon lemon juice
4 cups confectioners' sugar
To make vanilla sugar, tuck a whole vanilla bean into some granulated sugar. In a day or two, you have lovely vanilla flavored sugar.