Place 1 teaspoon jam in the center of each square. (marthastewart.com)
Spoon about 1 teaspoon jam into the center of each round of dough. (bonappetit.com)
Top each muffin with about 1/4 teaspoon peanut butter and 1/2 teaspoon jam and swirl with a toothpick being careful not to get too close to the edge. (ahappyfooddance.com)