Preheat your oven to 400°F and line a baking sheet with parchment paper.
Slice the spaghetti squash into rings and brush each ring with melted butter. Place them on the baking sheet.
Roast the squash for 30-40 minutes until tender; use a fork to separate strands.
In a large skillet, melt butter over medium heat. Sauté garlic and crushed red pepper until fragrant, then add shrimp and cook until opaque (about 2 minutes per side).
Remove shrimp and sauté spinach in the same skillet until wilted. Add vegetable broth and lemon juice, simmer briefly.
Return shrimp to skillet, mix in cooked spaghetti squash strands, and toss gently to combine.
Serve warm garnished with lemon wedges and chopped parsley.