1 and 1/2 cups (340g) unsalted butter, softened to room temperature
1 cup (200g) packed light or dark brown sugar
1/2 cup (100g) granulated sugar
5 large eggs, at room temperature
1/2 cup (120g) full fat sour cream, at room temperature
2 teaspoons pure vanilla extract
3/4 cup (180ml) milk, at room temperature
optional for topping: vanilla icing (see Note)
3/4 cup (150g) packed light or dark brown sugar
2 teaspoons ground cinnamon
1 teaspoon ground ginger
1 teaspoon ground cardamom
1/2 teaspoon ground allspice
Directions
Preheat the oven to 350°F (177°C) and grease a 10-inch Bundt pan.
For the cake: Whisk the flour, baking powder, and salt together in a large bowl. Set aside. Using a handheld or stand mixer fitted with a paddle or whisk attachment beat the butter, brown sugar, and granulated sugar together until creamed, about 2 minutes. Add the eggs, sour cream, and vanilla and beat on medium speed until combined. Scrape down the sides and bottom of the bowl as needed. The mixture will look curdled; that’s ok—it will come together when you add the dry ingredients.
Pour the dry ingredients into the wet ingredients, add the milk, and beat on medium speed it all until the batter is completely combined. Batter is thick, yet silky.
For the chai cinnamon swirl: Mix the swirl ingredients together in a medium bowl.
Pour half of the cake batter evenly into the prepared Bundt pan. Sprinkle the swirl ingredients evenly on top—it will be a thick layer of swirl! Cover evenly with remaining cake batter.
Bake for 55-70 minutes or until a toothpick inserted into the cake comes out clean with just a couple lightly moist crumbs. This is a large, heavy cake so don’t be alarmed if it takes a little longer in your oven.
Once done, remove from the oven and allow to cool for 2 hours inside the pan. Then, invert the slightly cooled Bundt cake onto a wire rack or serving dish. Allow to cool completely.
As the cake cools, prepare the icing. Try vanilla icing, the brown butter icing used on peach Bundt cake, the brown sugar icing used on pumpkin donuts, the maple icing used on banana scones, or homemade salted caramel. I used the brown butter icing in these photos. Drizzle icing over cake before slicing and serving.
Cover leftover cake tightly and store at room temperature for up to 2 days or in the refrigerator for up to 1 week.