Preheat the oven to 375°F (180°C). Lightly oil a 6-cup muffin tin or spray with nonstick spray.
Bring a large pot of salted water to a boil. Blanch each lasagna sheet 2–3 minutes until slightly softened but still pliable; repeat for all sheets and drain.
Gently fit one lasagna sheet into each muffin cup, pressing to form a cup shape without tearing the pasta.
In a small bowl, combine the drained ricotta with most of the basil leaves (reserve a few for garnish). Season with salt and black pepper to taste.
Transfer the ricotta mixture to a piping bag or use a spoon and place about 1 tablespoon of ricotta into each lasagna cup.
Spoon 1–2 tablespoons of marinara sauce over the ricotta in each cup to cover the filling.
Top each cup with a small amount of the cubed mozzarella. Drizzle lightly with olive oil and season with additional black pepper if desired.
Bake for 10–12 minutes, until the cheese is melted and the lasagna cups are cooked through and edges are golden and slightly crispy.
Remove from the oven and let cool 1–2 minutes, then garnish with reserved basil leaves and serve immediately.