Follow these step-by-step instructions for a foolproof meal that comes together in under 30 minutes. The beauty of this recipe lies in its simplicity and the synergy of cooking everything together on a single pan.

1. Preheat and Prepare: Begin by preheating your oven to 400°F (200°C). This high heat is crucial for roasting the asparagus to a perfect tender-crisp texture while quickly cooking the delicate fish. Line a large, rimmed baking sheet with parchment paper for the easiest possible cleanup. If you don’t have parchment paper, lightly grease the pan with olive oil.
2. Prepare the Asparagus: Wash the asparagus spears thoroughly under cold water. Pat them dry with a paper towel; removing excess moisture is key to roasting rather than steaming them. Identify the natural breaking point of the asparagus by holding a spear at both ends and bending it until it snaps. The woody, tough end will break off. Trim the rest of the bunch to the same length.
3. Create the Lemon-Garlic Marinade: In a small bowl, whisk together the ¼ cup of extra virgin olive oil, the minced garlic, the zest and juice of one lemon, ½ teaspoon of salt, and ¼ teaspoon of black pepper. This simple mixture is the heart of the recipe, providing all the core flavors.
4. Season the Asparagus: Place the trimmed asparagus spears directly onto the prepared baking sheet. Drizzle about half of the lemon-garlic oil mixture over them. Using your hands or tongs, toss the asparagus gently to ensure each spear is evenly coated. Spread them out into a single, even layer on one half of the baking sheet. Giving them space is vital for proper roasting.
5. Prepare the Tilapia: Pat the tilapia fillets completely dry with paper towels. This step is non-negotiable for achieving a beautiful, slightly golden surface on the fish. A dry surface allows the fish to roast rather than steam.
6. Season the Tilapia: Place the dry tilapia fillets on the other half of the baking sheet, next to the asparagus. Brush the remaining lemon-garlic oil mixture over the tops and sides of each fillet. Sprinkle the tilapia evenly with the smoked paprika (if using), the remaining ½ teaspoon of salt, and the remaining ¼ teaspoon of black pepper.
7. Arrange and Garnish for Baking: Thinly slice the second lemon. Place one or two lemon slices on top of each tilapia fillet. This not only looks beautiful but also infuses the fish with more citrus flavor as it bakes.
8. Bake to Perfection: Place the baking sheet in the center of the preheated oven. Bake for 12-15 minutes. The exact time will depend on the thickness of your tilapia fillets and asparagus spears. The dish is done when the asparagus is tender-crisp (easily pierced with a fork) and the tilapia is opaque and flakes easily when gently prodded with a fork.
9. Final Touches and Rest: Carefully remove the baking sheet from the oven. Garnish the entire pan generously with the freshly chopped parsley. Let the dish rest for a minute or two before serving. This allows the juices in the fish to redistribute, resulting in a more tender and flavorful bite.