Preheat oven to 350 degrees F. Line 8 muffin cups with paper liners.Prepare filling first. With a mixing spoon, beat together softened cream cheese and sugar.
Add egg and vanilla and stir until smooth. Set aside.In a mixing bowl, thoroughly stir together flour, cocoa powder, baking soda and salt.In a second mixing bowl, stir together oil, sugar, vinegar, egg, red food coloring, vanilla and sour cream.
Mix very well, then add flour mixture and stir just until blended.Measure out approximately 1/3 cup red mixture and set aside. Divide remaining red mixture among the 8 muffin cups – each cup should be a little over 1/3 of the way full. Spoon cream cheese mixture over red mixture, dividing evenly between all cups. Drop small spoonfuls of reserved red batter on top of cream cheese mixture, making a bulls-eye pattern.
Bake for 20-23 minutes.
Let cool on a wire rack. Carefully remove lift muffins from cups.Best serve slightly chilled