1

Line a 20cm square cake tin with baking paper, leaving some paper hanging over the edge of the tin to make it easier to lift out.

2

in a large pan, melt the low-fat spread over a low heat. Add 150g of the marshmallows and cook over a low heat for about 10 minutes, stirring often, until the marshmallows have melted and the mixture is smooth and combined.

3

Remove from the heat and stir in the rice krispies, mixing well so they are completely coated in the marshmallow mixture.

4

While the mixture is still warm, spoon it into the prepared tin and press lightly with a spatula to smooth the top. Scatter over the remaining marshmallows, then chill for at least 30 minutes to set. Lift out of the tin onto a chopping board and remove the baking paper, then cut into 16 squares and serve.