Preheat the oven to 400 °F.

In a skillet, heat 1 tbsp of olive oil over medium heat. Add ½ cup diced onions and 20 diced mushrooms to the pan and cook until the onions are translucent, or about 5 minutes. 

In a large bowl combine the mushroom and onion mixture with 1 lb of ground turkey, 1 egg, 2 cloves of garlic, ¼ cup parsley, half the Parmigiano-Reggiano, ½ tsp red pepper flakes, ½ tsp salt and pepper. Set aside. 

Slice the zucchini in half lengthwise. Using a spoon, scoop out the part of the zucchini that has seeds, creating a cavity. Place the zucchini halves in a baking dish. 

Spoon the turkey mixture into the cavity of each zucchini, generously filling each one. 

Pour the crushed San Marzano tomatoes overtop of the stuffed zucchini and cover the bottom of the dish as well.  Place the dish in the oven for 35 minutes, or until the zucchinis are fork-tender and the pork is cooked through.

About 5 minutes before the zucchinis are finished baking, make the salad. Add 6 cups arugula, 1 cup fennel, 2 tbsp olive oil, 1 tbsp fresh lemon juice, ½ tsp fine sea salt, freshly ground pepper to a large salad bowl and mix.

Remove from the oven, top with the remainder of the Parmigiano-Reggiano and enjoy immediately with the salad on the side.