In a skillet over medium heat, melt the unsalted butter. Add the diced apples, brown sugar, ground cinnamon, and ground nutmeg. Cook, stirring occasionally, until the apples are soft and caramelized (about 5-7 minutes). Set aside to cool.

In a mixing bowl, combine softened cream cheese, granulated sugar, egg yolk, and vanilla extract. Use a hand mixer and beat until creamy and smooth. Set aside.

In a large bowl, combine flour, sugar, baking powder, baking soda, and salt.

In a separate bowl, whisk together vegetable oil, eggs, plain yogurt, and vanilla extract.

Combine the wet and dry ingredients and mix until just combined—don’t overmix!

Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.

Fill each muffin liner halfway with batter. Dollop a spoonful of the cheesecake filling in the center of each, followed by a layer of caramelized apples. Top off with remaining muffin batter if necessary.

In a small bowl, mix the brown sugar and ground cinnamon for the topping. Sprinkle generously over each muffin.

Bake for 20-25 minutes, or until a toothpick inserted into the muffin comes out clean (not counting the creamy center). Allow to cool slightly in the tin before serving.