Step 1

Pre-heat oven to 190°C/375°F/Fan 170°C/Gas Mark Grease and line a 30 x 20cm rectangular cake tin with baking parchment.

Step 2

Melt the butter in a large saucepan then add the sugar, syrup and peanut butter and stir over a low heat until smooth.

Step 3

Remove from the heat and stir in the oats and vanilla and mix well. Pile into the tin and pack down well. Bake for 25 mins until lightly golden. Cool for 10 mins before marking into 20 bars using a sharp knife. Leave to cool completely before removing from the tin.

Step 4

To serve, dust lightly with icing sugar. Store in an airtight container for up to a week.