Place the steel-cut oats together with the unsweetened almond milk or coconut milk in a small saucepan. Add a pinch of Celtic sea salt right away and stir everything briefly.
Place the saucepan over low heat and bring the mixture to a gentle boil. Let the oatmeal simmer gently for five to eight minutes. Stir regularly to prevent the oats from sticking to the bottom and continue cooking until the porridge reaches the desired thickness.
Remove the pan from heat and let the oatmeal cool for one minute to prevent the protein powder from clumping in the hot liquid. Then add the whey protein isolate and Ceylon cinnamon. Stir everything together firmly until the powder is completely incorporated and a smooth consistency is achieved.
Transfer the warm oatmeal to a bowl and add the ground flaxseed or chia seeds. Top finally with the handful of fresh blueberries and serve immediately.