Preheat your oven to 170ºC (340ºF) and line two 20 cm (8-inch) baking pans with parchment paper.

In a large bowl, sift together the all-purpose flour, cornstarch, spices, baking powder, baking soda, and salt.

Cream butter and sugars until light and fluffy for about 3 minutes.

Beat in eggs one at a time, ensuring each is fully incorporated before adding the next.

Slowly add half of the dry mixture, then add sour cream, oil, and vanilla. Mix gently, followed by remaining dry ingredients.

Divide batter between pans and bake for about 28-30 minutes.

Let cakes cool in pans for 5 minutes, then transfer to a wire rack.

Prepare frosting by creaming together butter, sugars and adding cream cheese and vanilla bean paste until smooth.

Level cake layers if needed, frost between layers and around the cake, then dust with cinnamon if desired.