Heat up a pan of water and cook the macaroni according to the package instructions
In a separate pan, gently melt the butter
Once the butter has melted, take the pan off the heat
Stir in the protein powder until it has all been incorporated into the butter
Slowly add in the milk, about 50ml at a time and return the pan to the heat
Stir the mixture until it has dissolved into the milk. I find a whisk can help maintain a smooth sauce
Add the rest of the milk
Stirring continuously add the herbs, mustard and garlic powder
Add in the yeast flakes bit by bit. Make sure to stir continuously to keep the sauce smooth
Once all of the yeast flakes have been added the sauce should have thickened up. If you would like a thicker sauce, add more yeast flakes. If the sauce is looking too thick for you, stop adding the yeast flakes.
Add in the cooked macaroni and stir
Serve with your choice of toppings!