For the Blueberry Muffins, first mix the dry ingredients (flour, baking powder, baking soda and sugar) and the wet ingredients (butter, yogurt and eggs) separately in two bowls.
Then add the dry ingredients to the wet ingredients and mix briefly (not too long). Finally, gently fold in the blueberries. Pour the batter into the muffin tins and bake at 180° (top and bottom heat) for 25 minutes (or a little longer if needed) until golden brown.
Serve the blueberry muffins.