Blitz 175g of the strawberries in a food processor. Add the icing sugar then press the whole lot through a sieve to make a sauce. Set aside in the fridge.
Mix 225g of the crushed shortbread with the melted butter. Press this mixture into the base of a baking parchment-lined slice tin, about 18 x 28cm in size. Chill for 15 minutes. Take the ice cream out of the freezer to soften slightly.
Smooth the ice cream over the chilled shortbread base. Drizzle with the strawberry sauce then scatter over the fresh strawberries, dried strawberries and remaining shortbread. Return to the freezer for at least 2 hours or until firm then remove and leave to stand at room temperature for 10–15 minutes before cutting into bars with a sharp knife.