Shrimp Cavatappi with Mushrooms and Spinach

1 lb. large shrimp cooked
3 cups sliced mushrooms
3 tablespoons pine nuts
6 cups fresh spinach leaves (only used about 4 cups)
6 cups cooked cavatappi
8 tablespoons butter
2 tablespoons fresh garlic, peeled but leeft whole
Lemon Butter Sauce:
1 medium onion, diced
3 garlic cloves
1 cup dry white wine
2 cup heavy cream
1 cup lemon juice (freshly squeezed) (only used about 1/4 a cup, per many reviews)
1 teaspoon white pepper
1 lb lightly-salted butter (cut into tablespoons)

Preheat oven to 350 degrees.
Spread pine nuts over bottom of sheet pan and place pan in oven on top rack. Roast until golden brown, approximately 2 to 4 minutes.

For the Lemon Butter Sauce:
Melt 1 tablespoon butter in large skillet over medium-high heat. Sauté onion and garlic until translucent. Add white wine and reduce slightly more than 1/2, whisking occasionally. Add cream and reduce by 1/2. Add lemon juice and reduce by 1/2. Add white pepper. Reduce heat to low. Add remaining butter 2 tablespoons at a time, whisking continuously after each addition to completely incorporate butter. Continue to simmer, whisking until sauce just coats spoon.

In separate large skillet over medium-high heat melt the 4 tablespoons of butter. Add garlic and sauté until garlic is translucent. Stir in mushrooms, and pine nuts. Sauté several minutes until the mushrooms are softened.Now add spinach and wilt.Stir in shrimp to warm through. Toss together the pasta sauce and veggie shrimp mix. Serve with grated pecorino cheese.