In a large bowl, toss potatoes and carrots with 1 ½ Tablespoons olive oil, Italian seasoning, salt, and pepper. Place on a baking tray and bake for 25 minutes.
Meanwhile, add cut peppers to the large bowl, and toss with remaining ½ Tablespoon olive oil.
Flip or stir potatoes and add peppers to the potatoes on the roasting pan. Roast 10 minutes.
Meanwhile, in a small bowl, combine garlic butter ingredients. Add the shrimp to the large bowl, add the mixed garlic butter, and carefully toss.
Add shrimp to the pan and roast for an additional 6-8 minutes, or until shrimp is cooked through.
Remove from the oven, squeeze the ½ lemon over top (if using), and sprinkle with basil and parsley.