Lightly grease a muffin tin and set aside. Preheat the oven to 375 degrees F.
In a large bowl, mix together the flour, baking powder, salt, and baking soda.
In a separate bowl, mix together the oil, butter, sugar, peanut butter, eggs, buttermilk, and vanilla extract. Mix until everything is well-combined.
Mix the wet ingredients into the flour mixture and mix until there are no streaks of flour, but there are still lumps. Do not over mix.
Fill the muffin tins halfway full with the batter, then add a teaspoon of the jelly the middle of the batter. Top with more batter. Each cavity of the muffin tin should be about ¾ way full.
Put the muffin in into the oven and immediately drop the temperature to 350 degrees F. Bake for 18 - 20 minutes, or until a toothpick inserted comes out clean.
Best served the day they are made, but will keep in an air tight container for 5 days.