I recently made a lasagna with ground venison and Italian sausage. I wasn’t really paying attention to the fact that the recipe made enough for 2 lasagnas. Other than making another lasagna, which I don’t really want because there’s just two of us, and making spaghetti, which I don’t really want because I made spaghetti last week, what options do I have for about 4-5 cups of sauce?
Freeze it. I’ll keep for several months.
I second freezing it.
I third it. I freeze many leftovers and have never regretted it.
Yep. It’ll keep til you’re hungry for another lasagna.
If its just a basic pasta sauce with meat, it might be good made into a pot of minestrone.
With 4-5 cups, you have options. But agreed with most, and that I’d set aside a good bit and freeze for other applications later. But you could make (or just buy in many grocery refrigerated sections) a batch of pizza dough (not crust, the dough) and make it into calzones along with any other useful leftovers and cheese you might have in the fridge.
I pour my leftover sauce over chicken parts and top it with cheese to make a down and dirty (but still tasty) chicken “parmesan.” If I want it really down and dirty I use frozen chicken patties, or even nuggets.
It’s like I told my son when he moved into his first solo apartment and had to cook his own meals. “You have beef, chicken, pork and fish. Learn to use sauces.”
Absolutely freeze it ! It will keep damn near forever.
Look, you know how they have all those murder-shows for hunting? How they render the meat, wrap it, freeze it, and then dump the offal into a dumpster behind some random Walmart ?
The same way that we see that as Totally Insane is the way that they see freezing a Lasagna tray in the bottom of a deep freezer as totally insane. Look… it Works. OK, you might permanently stain a Tupper Ware container orange… but it works.
Look, don’t take my word for it. Ask anyone here.
( Private, so you know I didn’t bribe them. )
When I make lasagna I always have sauce left over. I separate it into serving-sized portions and freeze them. They become quick and easy spaghetti sauce for a future meal.
I guess you don’t have dogs. We don’t have these dilemmas at my house.
My lasagna/pasta/pizza sauce always has a lot of onion in it.
Toasted English muffin, apply sauce liberally, spread Mozz thickly, bake in oven of your choosing — mini-pizzas.
That was a regular after-school snack when I was in junior high school.
Part of this complete breakfast? Maybe with chocolate milk? 
I just got back from the store with hamburger buns for basically this. 40 years ago when I was first married, my wife would make these frequently. We called the Po Boy pizzas.
When do we eat? 
Early and often.
In the OP I missed the part about venison (I saw “lasagna” in the title and my eyes glazed over); I love venison but never thought about adding it to lasagna. Do you have to add anything to mellow out any gaminess?
My processor adds enough beef fat to it that it’s virtually indistinguishable from beef although I’ve never made a plain “hamburger” with it and have only used it as an ingredient. My wife is usually pretty susceptible to gaminess but she can’t tell a difference either. I think it also helps that the deer that I hunt are well fed on either corn or peanut fields.
I have a similar problem all the time because most of the good premade pasta sauces come in large jars that have too much sauce for even two or three servings of spaghetti. Once opened, it only keeps for a few days, so the solution is to freeze the remainder in a small airtight plastic container.
I have a similar solution to keeping a particular type of delicious store-made turkey gravy, except in that case I pour the gravy into little single-serving size plastic cups holding maybe 4 or 5 ounces and freeze those. I usually have a bag with about a dozen of them in the freezer