Chai Cinnamon Swirl Bundt Cake

all-purpose flour (spoon & leveled)

and 1/2 teaspoons baking powder

and 1/2 teaspoons salt

and 1/2 cups (3 sticks; 345g) unsalted butter, softened to room temperature

packed light or dark brown sugar

granulated sugar

large eggs, at room temperature

full fat sour cream, at room temperature

pure vanilla extract

milk, at room temperature

optional for topping: brown butter icing, salted caramel, or maple icing

packed light or brown sugar