Rinse berries, clean, sort and pat dry.
Mix butter with sugar until creamy, then mix in the egg. Stir in flour, almonds, salt, baking powder, baking soda and creme fraiche, stirring only until the dry ingredients are moist. Stir in the berries.
Place paper baking cups in the wells of the muffin tin. Fill with half the batter. Add 1 teaspoon marzipan to each muffin well and fill with remaining batter. Bake in a preheated oven at 180°C (approximately 350°F) for 25 minutes. Let muffins cool for 5 minutes in the tin, then lift out and allow to cool completely.