If using frozen shrimp, thaw them under cold running water for about 5-10 minutes. Once thawed, pat them dry with a paper towel and lightly season with salt and pepper.

In a large pot, bring salted water to a rolling boil over high heat. Add spaghetti and cook according to package instructions, around 8-10 minutes until al dente. Drain and reserve a cup of pasta water.

In a large skillet, melt 2 tablespoons of butter over medium heat. Add 2-3 cloves of minced garlic and sauté for about 30 seconds until fragrant. Toss in the halved grape tomatoes and cook for 3-4 minutes until softened.

Reduce the heat and add 4 cups of fresh spinach to the skillet, stirring until wilted (about 2 minutes). Gently fold in the shrimp and spaghetti. Toss together for about 3-5 minutes until shrimp are cooked.

Remove from heat and taste for seasoning. Adjust with salt, pepper, or reserved pasta water if needed. Serve immediately, garnishing with grated Parmesan cheese if desired.