Preheat your oven to 160ºC (320ºF) for a conventional oven. Line a 12-cup muffin tray with cupcake liners.

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

In the bowl of a stand mixer fitted with a paddle attachment or using a hand mixer, cream the butter and sugar on medium-high speed for about 3 minutes until fluffy.

Add the eggs one at a time, mixing well after each addition.

Reduce speed to low and gradually incorporate the sifted dry ingredients, mixing just until combined.

Add sour cream, vegetable oil, and vanilla extract. Mix until just combined. Do not overmix.

Divide the batter in half. Sprinkle the instant espresso powder into one portion and fold it in gently until the espresso is evenly blended throughout.

Alternate spoonfuls of the plain and espresso batters into each cupcake liner. Swirl with a toothpick to create a marbled effect.

Bake for 20-23 minutes, or until a toothpick inserted comes out clean. Cool on a wire rack, removing from the pan after 5 minutes.

For the Mascarpone Buttercream:

Let the butter and mascarpone sit at room temperature for 10 minutes.

Cube the butter and sift the powdered sugar.

Beat the butter on medium-high speed for 4 minutes, scrape down the bowl, then beat for 2 more minutes.

Add mascarpone and mix on low for 1 minute.

Add half the powdered sugar, vanilla bean paste, and Amaretto. Mix on low until combined.

Add the remaining powdered sugar and mix thoroughly, scraping down the bowl as needed. Finish with a final 1-minute mix.

Pipe the frosting using a large round tip (e.g. Wilton 1A) and dust with cocoa powder.