Preheat oven to 190ºC (375ºF). Cook pasta according to package instructions. 

In a medium size pan, heat oil and sauté garlic, onions, and mushrooms for 3 minutes. Add broccoli and continue cooking for 3 minutes. 

In a large bowl, mix together the cooked pasta, sautéed vegetables, pesto, lemon zest, and half the grated cheddar. Season to taste. 

Transfer mixture to an ovenproof baking dish and top with Parmesan and remaining cheddar cheese. Bake in the oven for 12 minutes or until cheese has melted and is golden brown.