Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Mix flour, baking powder and baking soda. Score the vanilla pod lengthwise and scrape out the pulp. Whisk the egg in a mixing bowl. Add vanilla pulp, 130 g sugar, buttermilk and butter and mix briefly with a whisk. Mix in the flour mixture only briefly. Spread the dough into the 24 wells of a silicone mini muffin baking tin. Bake in a hot oven for 10-12 minutes until golden brown. Remove from the oven, allow to cool slightly, remove from the trays and let cool on a cake rack.
In the meantime caramelise 3 tablespoons of sugar in a small pot until golden. Add the frozen raspberries and simmer over medium heat for about 10 minutes, stirring occasionally, until the caramel has dissolved. Pour the raspberries into a tall mixing bowl and puree with a hand blender. Pass the sauce through a fine sieve and allow to cool. Dust the muffins with icing sugar and serve with the raspberry sauce.
If you like, chop some more fruit into the dough.