Strawberry& Rhubarb Muffins

• 1 egg
• 1 granulated sugar for dusting
• 220 gr all purpose flour
• 180 ml milk
• 140 gr rhubarb (finely chopped)
• 100 gr granulated sugar
• 75 gr strawberries (sliced)
• 80 ml vegetable oil
• 9 gr baking powder
• 4 gr orange rind (grated)