Preheat the oven to 350°F. Line a 12-cup muffin tin with liners or lightly grease.
Blend the Medjool dates with a small splash of warm water until smooth to form a paste. If needed, soak the dates in hot water for 5 minutes first, then drain.
In a large bowl, whisk together the eggs, Greek yogurt, non-dairy milk, maple syrup, date paste, and vanilla extract until smooth.
In a separate bowl, mix the oat flour, baking powder, baking soda, cinnamon, salt, and ground flaxseed.
Fold the dry ingredients into the wet mixture just until combined.
Fill each muffin cup halfway with batter. Add 2 teaspoons of peanut butter and 1 teaspoon of jam to the center of each muffin. Cover with additional batter until the cups are about three quarters full.
Bake for 18 to 20 minutes, until the tops are lightly golden and a toothpick inserted into the side of a muffin comes out clean.
Cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
