Custard

• Add the cold milk, cornflour, sugar, ½ teaspoon vanilla and egg yolk to a cold pan. Whisk well to mix.
• Place over a medium heat. Stir constantly and bring to a simmer. Simmer for a minute, and remove from the heat. Set aside to cool.

Preheat the oven to 180 degrees (160 fan)

Rhubarb muffins

• If the rhubarb stems are large, cut them in half lengthwise. Then cut into 1cm pieces.
• Add the oats to the bowl of a food processor and blitz until powdery.
• Cut the apples from the core, and chop roughly. Add to the oats and blitz again until very finely chopped.
• Add the baking powder, 1 teaspoon vanilla, oil, honey and 2 eggs and blitz until thoroughly mixed.
• Stir in the rhubarb by hand.
• Line the muffin tin with 6 paper cases. Spoon a rounded tablespoon of muffin mixture into each case and level out.
• Add a heaped teaspoon of custard to the centre of each muffin.
• Top with the remaining muffin mixture and gently smooth the mixture over the custard. The custard should be fully covered.
• Bake at 180 degrees for 20 minutes until golden and set. Cool on a wire rack.