Preheat the oven to 170°C (325°F) and line a baking sheet with parchment paper.
Add coconut oil to a microwave safe bowl, then microwave until it has melted. Once melted, stir peanut butter, maple syrup and salt into the coconut oil.
In a large mixing bowl, combine oats with protein powder and cinnamon. Give it a quick stir, then add the peanut butter syrup mixture.
Evenly spread the protein oat mixture on the lined baking sheet.
Bake in hot oven for about 20-30 minutes, stirring halfway through to prevent burning and ensure even toasting. Once it is golden brown, remove from the oven and let cool for at least 1 hour before serving.
Once it has cooled, mix in any other ingredient such as walnuts, raisins, or chocolate chips.