Preheat your oven to 350°F (180°C).

In a large pot of salted boiling water, cook the rotini pasta according to the package instructions until al dente, usually about 8-10 minutes. Drain and set aside, reserving a bit of pasta water.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add chopped onion and minced garlic, sautéing for 3-5 minutes until the onion becomes translucent and the garlic is fragrant.

Stir in halved cherry tomatoes, artichoke hearts, and pitted Kalamata olives. Season with Italian seasoning, salt, and pepper. Cook for an additional 5-7 minutes until tomatoes soften.

In a large mixing bowl, combine the cooked pasta with the vegetable sauce from the skillet. Gently fold in the bocconcini and half of the grated Parmesan cheese.

Grease a baking dish with olive oil and pour the pasta mixture into it, spreading evenly. Top with remaining Parmesan cheese and drizzle with olive oil.

Place the baking dish in the oven and bake for 25-30 minutes until cheese is bubbling and golden.

Remove from oven, let cool slightly, and garnish with fresh parsley before serving.