The best blueberry muffins

Preheat the oven to 220ºC, gas mark 7. Line 2 x 12-hole muffin tins with 10 muffin tin liners (see tip for a homemade version), spacing them out so no muffins will be directly next to each other and they will have room to spread.

Make the streusel topping by combining the melted butter, demerara sugar and flour in a small bowl. Mix well with a spoon to create a thick, clumpy paste, then set aside to cool while you make the batter.

Combine the melted butter, oil and sugar in a large mixing bowl, then use a balloon whisk to beat in the eggs, yogurt and vanilla. Mix thoroughly until completely smooth.

Place 1 tbsp flour into a small bowl and add two-thirds of the fresh blueberries and all the frozen ones. Tumble them in the flour until well coated – this should stop them sinking in the batter.

Mix the remaining flour, baking powder, salt and cinnamon together in a separate bowl until evenly combined. Tip the dry ingredients into the wet ingredients and use a spatula to fold them together until just combined – overmixing here will create tough muffins. Add the flourcoated blueberries and fold briefly until evenly distributed.

Use an ice-cream scoop or tablespoon to divide the mixture between each muffin case. Fill right to the top – they will look quite full, but this creates the height desired. Use your fingers to break up the streusel topping, then sprinkle over each muffin and press the remaining fresh blueberries into the batter.

Bake for 5 minutes (adding steam if liked, see tips), then reduce the temperature to 190ºC, gas mark 5, and bake for 15-20 minutes more. The muffins should rise tall and be golden brown on top, with no raw patches. Allow to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely. These muffins are best enjoyed on the day they are made, but will keep for up to 3 days in an airtight tin.