Preheat oven to 350 degrees F. Line a 12-cup muffin tin with paper liners. 

In a large bowl, add flour, sugar, baking powder, and salt. Whisk together until combined. In a separate bowl, add milk, egg, peanut butter, banana, butter, and honey. Beat until creamy. Pour the wet mixture into dry ingredients, and mix gently until just combined.

Spoon the batter into the prepared muffin cups. Spoon a half of a tablespoon into each muffin cup; use a knife to gently swirl the jam into the batter.

Bake for 20-22 minutes, or until the tops begin to lightly brown. 

Optional: If desired, melt 2 Tablespoons additional peanut butter and drizzle over the cooled muffins.