Preheat your oven to 350°F. Grease and flour a 9×13-inch pan or line it with parchment paper. If using round cake pans, grease and line the bottoms for easy removal.
In a large bowl, whisk together the flour, spices, baking powder, baking soda, and salt. This helps evenly distribute the spices and ensures a light, fluffy crumb.
In another bowl, whisk together the oil, granulated sugar, brown sugar, eggs, sour cream, vanilla, and milk. Make sure the mixture is smooth and well blended.
Gradually add the dry ingredients to the wet ingredients, stirring just until combined. Don’t overmix. Pour the batter into your prepared pan and smooth the top.
Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool completely in the pan on a wire rack before frosting.
In a small saucepan, melt the butter over medium heat. Stir frequently until the butter turns golden brown and smells nutty, about 5–7 minutes. Let it cool for 10 minutes. Beat the brown butter with cream cheese until creamy. Add powdered sugar, vanilla, salt, and enough milk to reach a spreadable consistency. Frost the cooled cake and enjoy.