Preheat oven to 180°C (Gas mark 4/350°F). Line a 12 hole muffin tin with cupcake cases.
Make the crumble topping. If using coconut oil, gently melt first, then place all the crumble ingredients in a bowl and rub together with your fingertips until you have sticky crumbs. Place to one side for later.
Whisk the eggs with the maple syrup, vanilla extract and vegetable oil (or gently melted coconut oil).
Grate the apple and stir into the egg mixture, then add the flour, oats and baking powder to the bowl and gently fold in.
Tip in the raisins if using and gently stir them in until evenly distributed throughout the mixture.
Spoon the mixture into lined muffin tin, then sprinkle over the crumble topping, dividing it equally between all of the muffins.
Bake for 15-20 minutes until golden and cooked through. To check if they are cooked, stick a metal skewer or sharp knife into the centre of a muffin – it should come out clean.
Leave to cool on a wire rack. Once cool, top each muffin with 2 circles cut from dried mango or apricot and add raisins to make Gruffalo eyes.