Preheat the oven to 180C/375F/gas 4. Pulse the applesauce, eggs and vanilla in a food processor until well mixed (or stir well in a large mixing bowl). Add the melted oil and stevia (if using) and pulse or mix. Add the flour and baking powder and pulse gently a few times until just combined or stir gently until just combined. Stir through the raisins (tossing them in a small amount of flour first will help prevent them from sinking). Spoon into muffin cases lining a muffin tin and sprinkle a tiny bit of sugar over the muffins, if using. Bake in the preheated oven for 25-30 minutes, or until a skewer inserted into the centre of the muffin comes out clean. Allow to cool. Best eaten on the day they are made, but these do keep well for a few days in an airtight container. They also freeze well. I love them warmed through, but you can eat them cold if that's more your thing!