Preheat your oven to 350°F (175°C). Line a muffin pan with paper liners or grease each cup.

In a medium bowl, whisk together flour, baking soda, baking powder, and salt. Set aside.

In a large mixing bowl, mash bananas. Stir in granulated sugar, brown sugar, egg, vegetable oil, and vanilla extract.

Gradually add the dry ingredient mixture to the wet bananas, stirring gently until just combined.

If desired, fold in chopped nuts.

Spoon the batter into the muffin pan, filling each cup about three-quarters full.

In a separate bowl, beat cream cheese with granulated sugar until smooth. Mix in egg yolk and vanilla extract, adding milk if needed.

Dollop the cream cheese mixture atop the muffin batter, swirling gently with a toothpick.

Bake for 16-18 minutes, or until golden and a toothpick comes out clean.

Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.