Begin by preheating your oven to 350°F (175°C). Prepare a muffin tin by greasing it or lining it with cupcake liners.

In a mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Stir until everything is well blended.

In a separate bowl, whisk together the melted butter, eggs, buttermilk, red food coloring, vanilla extract, and vinegar until the mixture is smooth and uniform.

Slowly incorporate the wet ingredients into the dry mixture, stirring gently until just combined. Be careful not to overmix.

Melt the chopped chocolate in a microwave-safe bowl, heating in 30-second intervals and stirring until silky and smooth.

Gently fold the melted chocolate into the batter, ensuring it's evenly mixed.

Pour the batter into each muffin cup, filling them halfway. Place a teaspoon of softened cream cheese in the center of each cup, then top with more batter until nearly full.

Bake for 12-15 minutes, watching for the edges to firm up while the centers remain soft and gooey. Avoid overbaking.

Let the cakes cool in the tin for about 5 minutes, then carefully transfer them to a wire rack to cool slightly.

Serve the lava cakes warm, with a light dusting of powdered sugar if you like.