Dear Blog Fairy: Help!

So I tried a new recipe tonight, a very simple no-brainer sort of hamburger casserole recipe, but it wasn't until I had already added two cans of tomato paste that I realized the recipe said tomato sauce, and that I had also used diced rather than stewed tomatoes. I added extra water and a teaspoon of sugar to the recipe, but to no avail -- the casserole ended up with a very sharp, acid tomato flavor.

Can this casserole be saved? I really hope so, because I stupidly made a double recipe. Please, please, dear blog readers, tell me there is something I can add to solve this problem without turning the whole thing into soup?