Mix the flour with the salt and sugar. Whisk the eggs with milk and soda water. Combine the wet and dry ingredients then whisk mix well.
Add the butter to a non-stick frying pan on a moderate heat. Pour in half of the batter then sprinkle in the raspberries. Cook for about 3 minutes, until it is starting to firm, flip and cook for an additional 2 minutes or until brown. Gently with a spatula loosen the edges and slide onto a plate. Repeat for the second pancake
Serve with a large dollop of yoghurt and additional raspberries.