To make the sauce, purée the fruit with the lemon juice and sugar then sieve if liked.
To make the waffles, sift the flour, baking powder and bicarbonate of soda into a bowl then mix in the sugar. Lightly whisk the melted butter or oil, egg, vanilla and milk together in a separate bowl.
Heat up the electric waffle machine. Add the egg mixture to the dry ingredients then whisk until smooth. Spoon batter into the machine, close the lid and cook until waffles are browned and well risen.
Remove waffles from the machine, transfer to serving plates and cut in half. Top each one with a spoonful of crème fraîche or yogurt, summer fruits and a light dusting of sifted icing sugar then drizzle with fruit sauce to taste.