I start by heating the oven to 350°F (175°C). Then, I line my muffin tin with cupcake liners to keep things neat and easy to remove later.
In one bowl, I whisk together the flour, cocoa powder, baking powder, and salt. In another, I mix melted butter, sugar, and vanilla until smooth, then add in the egg. Slowly, I combine the wet and dry ingredients, alternating with the buttermilk, until I have a lump-free batter.
With my mixer, I beat the softened cream cheese until silky. Then, I add sugar, vanilla, and the egg yolk, mixing until creamy. This filling should look smooth and shiny before using.
I spoon just enough red velvet batter to fill about one-third of each cupcake liner. Then, I add a small scoop of cheesecake filling on top and swirl gently with a toothpick if I want a marbled effect.
I place the muffin tin into the oven and bake for about 20–25 minutes. The cheesecake should still have a slight wobble in the center when done—that’s the secret to a creamy bite.
After baking, I let them cool on a rack for 20 minutes. Then, I transfer them to the fridge to chill for at least 1–2 hours before serving. Trust me, the chilling makes all the difference in texture!