Preheat the oven to 425°F. Spray a standard muffin tin with nonstick cooking spray, or line with 12 paper liners.

In a medium-sized mixing bowl with an electric mixer, cream together the butter, vegetable oil, and sugars till smooth; about 3 minutes.

Add the eggs, beating to combine.

Add in the baking powder, baking soda, nutmeg, cinnamon, salt, and vanilla and mix until combined.

Stir the flour into the butter mixture alternately with the milk, beginning and ending with the flour and making sure everything is thoroughly combined.

Spoon the batter evenly into the prepared pan, filling the cups nearly full.

Bake the muffins in preheated oven for 15 to 17 minutes, or until they're light golden brown and a cake tester inserted into the middle of one of the center muffins comes out clean. Allow the muffins to cool for abut 15 minutes.

To fill the muffins with jelly or jam, place 3/4 cup of your favorite jelly or jam into a piping bag fitted with a Bismarck tip (Wilton 230) and pipe jelly or jam directly into the cupcake. If you don't have this tip, you can simply use a sharp paring knife to remove a piece from the center of the muffin. Next, spoon jam into the center of the cupcake and replace the top of the muffin.

Sprinkle with powdered sugar and serve.