Prepare the ingredients: Rinse the shrimp under cold water and pat dry with paper towels. Trim the woody ends from the asparagus and set aside.
Sauté the garlic: In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the minced garlic and sauté for about 1-2 minutes until fragrant, being careful not to let it burn.
Cook the shrimp: Increase the heat to medium-high and add the shrimp to the skillet. Season with salt, pepper, and red pepper flakes if using. Cook for about 2-3 minutes on each side until the shrimp are pink and opaque. Remove shrimp from the skillet and set aside.
Cook the asparagus: In the same skillet, add the remaining tablespoon of olive oil. Add the asparagus and sauté for about 5-7 minutes, stirring occasionally, until the asparagus is tender but still bright green.
Combine: Return the cooked shrimp to the skillet. Add the lemon juice and zest, stirring everything together until combined and heated through. Cook for an additional minute.
Serve: Transfer the mixture to a serving plate and garnish with chopped parsley.