A cornstarch slurry is used to thicken almost any kind of sauce and it only takes a few seconds to make, per Baking Kneads. Simply add 2 tablespoons of cornstarch to 1 cup of water or to the liquid from the baked beans (scoop it out into a separate bowl and let it cool first) and mix. Once the starch is thoroughly incorporated, pour the slurry into the baked beans dish and stir. Let this simmer for a minimum of 10 minutes so the starch has time to work its magic.
Our Everyday Life suggests that if you don’t have cornstarch on hand, you can also use arrowroot or potato starch, as well as flour. But when using flour, be sure to simmer the beans for a little longer so the flour can break down and dissolve properly.
You can also scoop out some of the beans and mash them, per Our Everyday Life. Be sure to use a potato masher to mash about 2 to 3 cups worth; You’ll want to get the beans into a thick, paste-like consistency. Add the mashed beans back into the baked beans dish, stir and let this simmer together for another 15 minutes or so.
Next time you come face-to-face with a runny baked beans sauce, you can smile back at it and know there is more than one way to fix it.