Preheat the oven to Gas 3/160C/140 fan assisted oven. Line a 12 hole muffin tin with paper cases. Place the butter in a large bowl and cream until soft. Add the sugar and beat until the mixture becomes light and fluffy.
Whisk the eggs in a small bowl and gradually add them to the butter mixture, continually stirring. Next stir in the milk and vanilla then sift in the flour, baking powder and salt and gently fold to combine.
Cut up about 8 strawberries into small chunks and mix into the cake mixture. Equally divide the mixture between the muffin cases.
Place in the oven and bake for 20-25 minutes or until well risen, slightly golden and springy when you touch them. Allow the cakes to cool for 5 minutes and then remove from the tin and place them on a wire rack so that they can cool completely.