Preheat oven to 425 degrees F. Lightly oil a baking sheet or coat with nonstick spray.
In a small bowl, whisk together butter, garlic, lemon juice and Italian seasoning; reserve 2 tablespoons and set aside.
Place asparagus in a single layer onto one side of the prepared baking sheet. Stir in 2 tablespoons olive oil; season with salt and pepper, to taste.
Place tomatoes in a single layer in the middle of the prepared baking sheet. Stir in remaining 2 tablespoons olive oil; season with salt and pepper, to taste.
Place tilapia in a single layer onto the opposite side of the prepared baking sheet. Drizzle with butter mixture.
Place into oven and bake until fish flakes easily with a fork and the tomatoes begin to burst and have softened, about 11-13 minutes.
Serve with reserved butter mixture, garnished with parsley, if desired.