1-Preheat oven to 325°F (163°C). Grease and line two 8-inch or 9-inch cake pans with parchment paper.

2-Prepare the cinnamon swirl by mixing ¼ cup light brown sugar, 2 tablespoons all-purpose flour, 1 teaspoon ground cinnamon, and 2 tablespoons melted butter. Set aside.

3-In a medium bowl, whisk together dry cake ingredients: 3 cups flour, 1 tablespoon baking powder, 2 teaspoons pumpkin pie spice, ½ teaspoon cardamom, 1 teaspoon cinnamon, ½ teaspoon ginger, ¼ teaspoon nutmeg, and ½ teaspoon salt.

4-In a stand mixer, cream 1 cup granulated sugar, ½ cup light brown sugar, and 3 large eggs until light and fluffy (3-5 minutes).

5-Add ½ cup vegetable oil, 2 teaspoons vanilla extract, and canned pumpkin puree; mix until combined.

6-Gradually add dry ingredients at low speed, mixing till just combined.

7-Divide batter evenly between pans, smoothing tops. Drop spoonfuls of cinnamon swirl mixture atop batter and gently swirl with a knife or toothpick to create a marbled effect.

8-Bake for 30-35 minutes until a toothpick inserted in the center comes out clean. Cool in pans for 10 minutes, then transfer to wire racks to cool completely.

9-To make buttercream, beat 1 cup butter until creamy. Gradually add 1 cup light brown sugar; beat well. Add 2 teaspoons cinnamon, 4 cups powdered sugar (in batches), 3-4 tablespoons heavy cream, 2 teaspoons vanilla extract, and a pinch of salt. Beat on low until combined, then high until fluffy. Adjust cream for desired consistency. Use spatula to gently remove air bubbles.

10-For white chocolate ganache, heat ¼ cup heavy cream until just boiling, pour over ¾ cup white chocolate chips. Let sit 3-4 minutes, then stir gently until smooth.

11-Level cake layers if needed. Place one layer on a serving surface, spread buttercream evenly, drizzle with ganache. Add second layer, repeat frosting and ganache.

12-Apply a thin crumb coat of buttercream around the cake; chill 10-15 minutes. Finish applying final buttercream layer and drizzle remaining ganache. Let cake reach room temperature before serving.