Place the cannellini beans, fennel and celery in a small bowl. Drizzle with a little olive oil and sherry vinegar. Season with salt and pepper. Toss to combine and set aside.
Preheat oven to 200˚C, fan on. Place mushrooms on a baking tray. Drizzle with olive oil and season with salt, pepper and garlic powder. Roast for ± 7 minutes until tender and juicy, but retain some bite.
Allow the mushrooms to rest. Once the mushrooms have rested, assemble the salad.
To assemble
Layer the baby leaves and apples on a serving platter. Spoon over the marinated bean mixture.
Top with the roasted mushrooms. Sprinkle with walnuts and fennel fronds. Season lightly.Drizzle everything with a little extra sherry vinegar and olive oil and serve!