Preheat oven to 350F. Grease a 12 muffin pan with oil, or line with cupcake holders.
Prepare flax egg by combining 1 tablespoon flax and 3 tablespoon water. Set aside for at least five minutes.
Pulse rolled oats in a food processor until they are a flour-like consistency. Stir together dry ingredients: rolled oats, flour, baking powder, and salt. Set aside.
Mix peanut butter, oil, and brown sugar together in medium mixing bowl. Pour dry ingredients into peanut butter mixture, stirring to combine. Mash up banana with a fork and add to mixture. Slowly pour in soy milk and apple cider vinegar, mixing until batter like consistency; it should be spoonable, not pourable.
Fill each of the 8 muffin tins half way full. Add a teaspoon of raspberry jam to the center of each muffin. Add remaining batter until about ¾ full. Fill the four empty muffin tins with water so that the muffins don't burn. Bake for 20-25 minutes, or until a toothpick inserted in the center comes out clean.
Notes
Batter makes 8 medium sized muffins or 12 small muffins. If using a 12 muffin tin, fill the 4 empty tins halfway full with water. This makes it so that the muffins don't brown too much or burn.