Stuffed Pasta Shells with Creamy Spinach, Mushrooms, and Shrimp

Ingredients

• 12 oz jumbo pasta shells (about 20 shells)
• 8 oz white or cremini mushrooms, sliced (about 2 cups)
• 3 cloves garlic, minced (about 1 Tbsp)
• 1 small onion, finely chopped (about ½ cup)
• 4 cups fresh spinach leaves, roughly chopped
• 1 lb shrimp, peeled, deveined, and chopped into bite-size pieces
• 4 oz cream cheese, softened (½ standard block)
• ½ cup heavy cream
• ½ cup grated Parmesan cheese, divided
• ½ tsp salt (plus more to taste)
• ¼ tsp black pepper
• Chopped fresh parsley