Preheat oven to 425 degrees F. Line a muffin pan with liners and set aside. In a large bowl, whisk together flour, cocoa powder, baking powder and salt.
In another bowl, whisk together the eggs and 1 cup granulated sugar. Add vegetable oil, buttermilk, sour cream and vanilla extract. Pour wet ingredients into dry and gently fold until the batter just comes together. Set aside.
In another bowl, whisk together the cream cheese filling ingredients until super smooth. You can use a hand or stand mixer for this if you desire.
Fill muffin cups a little less than halfway with chocolate batter (I like to use a cookie scoop to help keep them even). Top each with 2 tablespoons cream cheese filling. Top with another scoop of chocolate batter. Finally, top with 1 tablespoon more of cream cheese filling. Take a toothpick and swirl each one.
Bake for 14 to 16 minutes, until a toothpick comes out clean. Store in an airtight container at room temperature.