01 - Preheat the oven to 350°F. Line a 24-cup mini muffin tin with paper liners or lightly grease each cup with butter or cooking spray.
02 - In a medium bowl, whisk together melted butter and granulated sugar until smooth and well combined. Add the egg, vanilla extract, and red food coloring. Mix thoroughly until uniform in color.
03 - Sift the all-purpose flour, cocoa powder, and salt into the wet mixture. Stir gently until just incorporated—avoid overmixing to prevent tough brownies.
04 - In a small bowl, beat the softened cream cheese with granulated sugar, egg yolk, and vanilla extract until smooth and creamy. Ensure no lumps remain.
05 - Spoon approximately 1 tablespoon of brownie batter into each prepared muffin cup, filling about halfway. Top each with 1 teaspoon of the cream cheese mixture.
06 - Use a toothpick or skewer to gently swirl the cream cheese into the red velvet batter, creating a marbled pattern. Avoid mixing completely.
07 - Bake for 23 to 25 minutes, or until centers are set and a toothpick inserted comes out with a few moist crumbs. The tops should be slightly firm but not dry.
08 - Let the brownie bites cool in the pan for 10 minutes before transferring to a wire rack. Cool completely before serving to allow the cream cheese swirl to set.