Make a simple muffin batter and fill the muffin tins 1/2 way, dollop a tsp of jam, and then more batter. Top with a tsp of jam and then work it into the batter lightly with a skewer.
2 1/2 cups all-purpose flour
1/2 cup white sugar
1 tbls baking powder
1/2 tsp salt
1 cup buttermilk
1/2 cup butter, melted
1 large egg
1 tsp vanilla extract
Zest of one lemon
1/2 cup jam or preserves
Preheat oven to 400F.
Line a muffin tin with paper liners and then spray with non stick spray.
In a large bowl, combine the flour, baking powder and salt, mix and set aside.
In the bowl of a stand mixer, beat butter and sugar. Add egg, zest and then vanilla. Add the dry mixture and then the milk and mix until just combined being careful not to overmix.
Fill the muffin-pan cups one-third full with batter. Drop a teaspoon of preserves on top of the batter. Top with the remaining batter and then another tsp of jam. Swirl lightly with a toothpick.
Bake until a toothpick inserted in the center of the muffin comes out clean, 20-23 minutes