For the muffins:
1 Preheat the oven to 180 degrees or 160 degrees if using a fan oven. Grease and line a six-hole cupcake or muffin tin with muffin cases. If using parchment paper, cut squares of parchment paper a few centimetres larger than the diameter of your muffin holes, crinkle and crumple the paper in your hands, then push the paper into the muffin tin.

2 In a large bowl, sift in the flour, then add the ground almonds, caster sugar, orange zest and salt. Mix well and set aside.

3 In a microwave proof bowl or small saucepan, melt the butter until just melted, and set aside to cool slightly while preparing the remaining wet ingredients.

4 In another bowl or large jug, mash the banana with a fork until soft, then add the vanilla extract, egg, milk and cooled melted butter. Whisk together until well combined.

5 Add the wet ingredients to the dry, and whisk until smooth. Take care not to overmix the batter.

6 Finally, fold in the mixed berries, and divide the batter between the six muffin cases. Set aside while preparing the topping.

For the topping:
1 Mix the light brown sugar, oats and flaked almonds together in a small bowl.

2 Divide the 50g of mixed berries between the muffins, and sprinkle the topping on top of each muffin.

3 Bake the muffins in the preheated oven for 25-30 minutes until the muffins are lightly golden and the topping looks delicious and crunchy. Insert a skewer or knife into the centre of one of the muffins and if it comes out clean, it is cooked.

4 Remove the muffin tin from the oven and leave to cool for five minutes in the tin, before turning out onto a wire rack and allowing to cool completely.

5 The baked muffins will keep in an airtight container for two days, and can be frozen for up to a month.