In a blender, chop your spinach slightly, add the eggs and milk and mix. Pour in a large bowl and add the bread; let it stand until the liquid is absorbed. Stir in the onion, carrots, cheeses and seasonings. Crumble beef over the mixture and mix well.
Shape into a loaf and place in a baking dish/pan lightly coated with cooking spray place a rack inside the dish/pan. Bake uncovered at 350° for 45 minutes.
After 45 minutes spoon barbeque sauce over the meat loaf. You can add extra barbeque sauce during the baking time if you want. Bake 30 minutes longer or until the meat is no longer pink. If you have a meat thermometer bake until 160°. Let the meatloaf rest about 10 to 15 minutes before serving.
Note: I have also done this in a crockpot. Bake on low for about 6 to 7 hours.