1. Preheat the oven to 200 degrees. Brush muffin cases with oil or line with muffin trays.

2. Stir together the flour, sugar, salt and baking powder. Then mix the oil, eggs and milk into the flour mixture. Then add the blueberries. Pour mixture evenly onto muffin cases, level with tops. Then sprinkle some other ingredients on top to make it crunchy.

3. Crunchy topping: Mix together 100g sugar, 50g flour, 50g butter and 1.5 teaspoons cinnamon with a fork and sprinkle over the muffins.

4. Bake in the preheated oven for 20-25 minutes.