- Step 1
Preheat oven to 180C or 160C fan-force. Grease and line base and 2 long sides of a 20cm x 30cm lamington pan.
- Step 2
Whisk peanut butter and vanilla in a large bowl until combined. Stir in sugar until combined. Sift flour and bicarbonate over peanut mixture (tip in the flour kernels). Add oats and milk and stir to combine. Transfer to prepared pan and press surface with hands to level. Bake for 20 minutes or until a skewer inserted in centre comes out clean. Cool in pan.
- Step 3
Combine melted chocolate and oil in a small bowl. Spread over slice. Sprinkle with peanuts. Stand for 1 hour or until set. Cut into 20 pieces.
Slice will keep wrapped in plastic for 1 week or you can freeze it for up to 1 month.