Place the milk in a large bowl and sprinkle over the pudding mix. Use electric beaters to beat for 1 minute or until combined. Place in the fridge, stirring once, for 5-8 minutes or until slightly thickened. Cut 350g strawberries into 1cm pieces. Cut the remaining strawberries in half and set aside.
Meanwhile, cut each sponge cake in half horizontally. Trim 3 sponge cake pieces to fit into a 20cm square dish, reserving the offcuts and remaining piece. Place 1 sponge cake piece into the base of the dish, using reserved offcuts and untrimmed sponge to fill the gap along 1 side don’t( worry if it doesn’t fit perfectly).
Stir the chilled pudding mixture and spoon half over the sponge layer. Sprinkle with half the strawberry pieces.
Top with another trimmed sponge piece, filling gaps with offcuts. Cover with remaining pudding mixture and strawberry pieces.
Top with remaining sponge piece, filling gaps. Spread evenly with cream. Scatter with pistachios and halved strawberries to serve.
