Part 4/5:
Now, pour in the skimmed milk and use a spatula to combine until you achieve a thick, homogenous mixture resembling Nutella with oats. If using casein protein, be prepared to add water gradually until you reach the desired consistency.
Once your mixture is ready, prepare a baking tin (approximately 20 cm by 8 cm) lined with parchment paper. Transfer the mixture into the tin, spreading it evenly to cover the entire base, which will yield about six oat bars.
Preheat your oven to 200°C (400°F) and bake the mixture for approximately 25 minutes. After baking, let the bars cool on a plate for around 20 minutes. This cooling period is crucial, as it allows the bars to firm up for easier cutting.