Mushroom and Spinach Stuffed Shells

Ingredients

• 340 g (3/4 lb) giant shells
• 284 g (10 oz / 1 bag) spinach, trimmed, washed and spun dry, coarsely chopped
• 75 ml (1/3 cup) olive oil
• 900 g (2 lb) mushrooms, sliced thinly
• 250 ml (1 cup) 35% cream
• Salt and freshly ground pepper, to taste
• 50 ml (1/4 cup) basil pesto
• 500 ml (2 cups / 190 g) Mozzarella cheese, grated
• 1 L (4 cups) tomato sauce