How to cook
In a large bowl, mix the walnuts, baking soda, salt, baking powder and cinnamon. Stir and then pour the milk over them. Let it sit for 20 minutes for the oats to soften well.
In another bowl, break the egg and add the sugar, then add the oil in a thin stream. Lastly, add the walnuts (they are optional, according to taste) and grated apples (beat them with a fork or whisk, but not a mixer).
Pour the mixture into oats and stir gently, don't overdo it. Put baking paper in the muffin forms and distribute the mixture into them evenly.
Bake the muffins in a preheated 356°F (180 °C) oven for about 20 minutes.