Preheat oven to 375°F. Grease a muffin tin and set aside.
In a large bowl combine flour, baking powder, salt, nutmeg and sugar.
Make a well in the center of the dry ingredients, and add egg, buttermilk, vanilla and oil.
Gently combine until no more flour streaks remain.
Fill each muffin tin about ¾ full, using all the batter.
Top with a spoonful of granulated white sugar.
Bake on center rack for 15-16 minutes or until set and the center springs back.
Allow muffins to cool in the tin about 5 minutes. Remove and place on cooling rack.
Using the end of a chopstick or other small kitchen tool, poke a hole in the center of each muffin, making room for the jam.
Place jam in a small zip-top bag and cut a ¼" hole in one lower corner. Fill each muffin center with jam. You can fill as much or as little as you like. If the jam jams up (haha), use the chopstick to gently push the jam down further to make room for more.
Enjoy!