In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.
Add the shrimp to the skillet and season with salt, pepper, and red pepper flakes if using. Cook for 2-3 minutes on each side until the shrimp turn pink and opaque. Remove the shrimp from the skillet and set aside.
In the same skillet, pour in the heavy cream and bring to a gentle simmer. Stir in the lemon juice and chopped spinach, cooking until the spinach wilts, about 2-3 minutes.
Return the cooked shrimp to the skillet and stir to combine, allowing everything to heat through for another 2 minutes.
Taste and adjust seasoning if necessary. Serve immediately, garnished with fresh parsley.