Brush the inside of 16 paper baking cups with melted butter. Place each cup inside another paper cup. Place in a muffin pan. Pre-heat the oven to 400° degrees.
Mix the flour, sugar, salt and baking powder together in a mixing bowl.
Beat the eggs well. Add vanilla extract. Stir in the crème fraiche. Add the flour mixture and mix carefully; don’t stir too long!
Fill the prepared baking cups with the batter. Press one teaspoon of preserve into the centre of the dough in each one.
Bake at 400° on the middle shelf for 12-15 minutes. Cool and serve.