Peanut Butter and Jam Muffins

1 cup all-purpose flour
3/4 cup whole wheat flour
1/4 cup granulated sugar
1/4 cup packed dark brown sugar
1 tablespoon baking powder
1/2 teaspoon salt
1 1/4 cups fat-free milk
1/3 cup creamy peanut butter
1/4 cup egg substitute
2 tablespoons butter, melted
1 teaspoon vanilla extract
Cooking spray
1/4 cup strawberry jam

Preparation
Preheat oven to 400°.
Lightly spoon flours into dry measuring cups; level with a knife. Combine flours, sugars, baking powder, and salt in a large bowl; stir with a whisk. Make a well in center of mixture. Combine milk and next 4 ingredients (through vanilla); add to flour mixture, stirring just until moist.
Spoon batter into 12 muffin cups coated with cooking spray. Fill each cup half full with batter. Spoon 1 teaspoon jam into each cup. Spoon remaining batter on top to cover jam. Bake at 400° for 20 minutes or until muffins spring back when touched lightly in center. Let cool in pan 5 minutes. Remove from pan, and cool on a wire rack.