Wash the kale leaves. Remove the ribs and chop them into bite-sized. Place them into a large salad bowl and add 1 tbsp of olive oil. Using your hands massage the kale for 2 minutes. Set aside.
Chop the mushrooms. Add them to a pan with 1 tbsp of olive oil. Add salt and pepper to taste. Saute for about 10 minutes or until brown.
In the meantime, peel the onion and remove the 2 edges. Using a mandolin, cut your onion into thin slices. Place in the salad bowl with the kale.
Chop pecan nuts. Add them to the salad bowl.
At this time of the recipe, it is perfect to do the dressing (see below*). Set it aside.
Last (to avoid the apple to brown), wash the apple (don't peel), cut it into 4 pieces, and remove the core. Using the same mandoline, slice the apple into thin slices.
Add the sliced apple to the salad bowl.
When the mushrooms are ready, add them to the salad and mix well. Pour the dressing and enjoy immediately.