Rinse the raspberries and pat dry.
Preheat the oven to 180°C (approximately 350°F).
Mix the flour with ground almonds and baking powder in a bowl. Beat the egg with the sugar, vanilla sugar, salt, oil and buttermilk. Stir in the flour mixture until the dry ingredients are moist.
Line a muffin tin with baking cups. Fill the cups with half of the batter. Dust the raspberries with a little flour and then place the berries on top of the batter in the muffin cups. Cover the berries with the remaining batter and bake in the preheated oven for about 25 minutes.
10 minutes before the end of the baking time sprinkle the sliced almonds on top of the muffins.
Remove the baked muffins from the oven and allow to cool briefly before releasing from the muffin tin.