Place half of the strawberries into a large bowl with most of the sugar and all of the lemon juice. Using a fork, mash well. Mix the remaining quartered strawberries into the mashed strawberry mix.
Season the mixture with the pepper and chopped mint and adjust the sweetness to taste with the remaining sugar. Cover and leave to marinate in the fridge for 30 minutes.
To serve, place the strawberries into bowls and spoon over clotted cream.