To simplify this even more, I skipped the broiler and just let the cheese melt with the lid on the skillet on the stovetop for an extra minute or so. I don't normally keep frozen mixed veggies in the freezer but I always have frozen peas. So I improvised using frozen peas along with fresh shredded carrots and chopping them into smaller pieces. Used a little extra veggies overall and just slightly less cheese to lighten up the dish. Turned out great and will likely become a weeknight staple!