Preheat your oven to 350°F (175°C). Gather your ingredients and prepare your muffin pan.

In a medium saucepan, combine the melted butter, whole milk, and granulated sugar. Stir until the sugar dissolves.

Allow the mixture to cool slightly, then whisk in the eggs until fully combined.

Stir in the pumpkin puree, baking powder, pumpkin pie spice, and salt until smooth.

Gradually add the flour, mixing gently until incorporated.

Grease your muffin pans with cooking spray or melted butter.

Pour the pumpkin batter into the prepared muffin pans, filling each cup about 3/4 full.

Bake for 25-30 minutes, until a toothpick inserted comes out clean.

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