Preheat your oven to 200C/400F/Gas mark 6 and line a muffin tin with 8 liners or lightly grease the pan.
Hull and quater the strawberries and place them to one side.
In a large mixing bowl gently whisk together the flour, baking powder and salt.
In a microwavable bowl melt the butter for around 30 seconds on a medium setting. Allow the butter to slightly cool if it feels too warm. You don’t want your egg to scramble.
Add in the egg, milk, sugar, vanilla and lemon juice and whisk everything together.
Pour the wet ingredients into the dry and gently fold everything together.
Fold in the strawberries. Then divide the batter between the muffin liners and sprinkle the demerara sugar over the tops of the muffins if you are using it.
Pop the muffin pan in the oven and bake for 25 minutes. Once the muffins are baked through take them out of the oven and allow them to sit in the pan for a few minutes before transferring them to a wire rack to fully cool down.
These muffins will last 4 to 5 days in an airtight container. And can be frozen up to 3 months.