Preheat the oven to 350°F (175°C) and line a muffin tin with paper liners.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a large bowl, cream together the softened butter and granulated sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk, and mix until just combined.
In another bowl, beat together the softened cream cheese, powdered sugar, and cinnamon until smooth.
Fill each muffin cup halfway with the batter, then add a spoonful of the cream cheese mixture on top, followed by another layer of muffin batter to cover.
Sprinkle the tops with brown sugar for added sweetness and crunch.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.