Combine the broccoli, garlic, 1 tablespoon oil and some salt and pepper in a medium bowl. Add the remaining tablespoon oil to coat the bottom of a large ovenproof skillet, preferably cast iron. Add the cheese in an even layer followed by the broccoli. Roast until the broccoli is slightly browned and the cheese is golden brown and crispy, about 15 minutes.
Meanwhile, combine the ranch, sriracha, lime zest and juice in a small bowl. Remove the skillet from the oven and drizzle the sauce all over the broccoli.