Leave lasagna to thaw enough to be cut with a knife. I put mine in the fridge the night before. It was definitely still frozen when I pulled it out of the fridge but cut-able. As long as it’s not frozen solid you’re good to go. Cut into 1 inch slices and place in crock pot.
Cover with chicken broth. I used 9 cups of water and 7 bouillon cubes (my cubes each make 1 C broth).
Cook on high for 3 hours or until heated through.
Season with Italian seasoning and garlic salt to taste. Top with a sprinkling of shredded mozzarella if desired.