Preheat the oven to 200C | Gas mark 6.
Place the oats on a baking tray and place in the middle of the oven for 15 minutes or until golden, stirring half way through to make sure they don't burn.
Line a 3" x 6" baking tray with baking parchment and set aside.
Place the oats into a mixing bowl, stir in the protein powder then add the margarine, peanut butter and mix until combined.
Transfer the mixture into the baking tray and using the back of a spoon, spread and flatten the mixture until even. Place in the fridge to set whilst making the chocolate ganache.