Preheat oven to 375ºF.
Line muffin tin with baking cups or spray with cooking spray. Set aside.
Combine flour, salt, baking powder, and sugar in the bowl of your mixer.
Stir in peanut butter until crumbly.
Whisk together eggs, milk, vanilla extract, and coconut oil.
Pour egg mixture in and mix on low speed just until combined.
Fill each cup halfway with batter.
Make a small well in the center with the back of a spoon and spoon in one tablespoon of jam into the center.
Divide remaining batter among muffins cups.
Bake for 18 to 20 minutes.
Let cool slightly before serving.