Preheat the oven to 425°F. Grease a large baking sheet with 2 tbsp olive oil.

Break lasagna noodles into large pieces. Cook in salted boiling water until al dente according to package instructions, then drain and toss with 1 tbsp olive oil to prevent sticking.

Heat the remaining 1 tbsp olive oil in a large skillet over medium-high heat. Cook onion until softened, then add ground beef. Break apart and cook until browned, about 7 to 10 minutes. Drain excess grease and season with Italian seasoning, garlic powder, ¼ tsp salt, and ¼ tsp pepper.

Stir in marinara sauce and chopped spinach. Set aside.

On the prepared sheet pan, layer half the noodles, half the meat sauce, and half the mozzarella. Repeat with the remaining noodles and sauce.

In a small bowl, stir together ricotta, Parmesan, and the remaining salt and pepper. Spread evenly over the top layer and sprinkle with the rest of the mozzarella.

Bake for 20 minutes, until the cheese is melted and bubbly.

Let cool for 5 minutes, garnish with fresh basil, and serve warm.