For the crumble topping:
50g cold butter, diced
50g plain flour
25g porridge oats
50g demerara sugar
1 tsp ground cinnamon
For the muffins:
375g self-raising flour
125g soft light brown sugar
1 medium egg, beaten
100g butter, melted and cooled
200g rhubarb, sliced lengthways and chopped
50g caster sugar
1. Preheat the oven to 200C (400F). Line a 12-hole muffin tin with paper cases.
2. To make the crumble, rub the diced butter into the plain flour and oats until the mixture resembles coarse breadcrumbs. Add the sugar and cinnamon, mix again and set aside.
3. For the muffins, sift the flour into a bowl, add the soft brown sugar and mix. Whisk together the egg, milk and cooled, melted butter.
4. In another bow, mix the chopped rhubarb with the caster sugar and 2 tbsp cold water.
5. Add the egg, milk and butter to the flour and sugar. Add the rhubard mixture and stir to combine. Do not over mix.
6. Divide this mixture between the muffin cases and then sprinkle over the crumble mix, pressing it gently into place.
7. Bake for 20-25 minutes. Leave in the tin for 5 minutes then move to a wire rack to cool.