For a successful sloppy joe, the sauce needs the right consistency. You don’t want it too thick, but the filling shouldn’t fall out, and the bun shouldn’t be soggy, either.
As your beef simmers, the sauce should thicken up. If it needs a little help, add a mixture of equal parts cornstarch and water. If the mixture is too thick, add water or stock.
Mix ½ teaspoon of baking soda into a tablespoon of water for every 1¼ pounds of ground beef. Sprinkling baking soda onto onions before frying will soften them as well.
Breaking down the meat into fairly small and consistently-sized pieces will enhance the velvety texture all the more while browning, and make it easier to eat.
Big pieces of meat are more likely to fall out of the sandwich, making it sloppier than intended. While you can use a spatula to break it down, a potato masher will keep it even.
To create a richer, deeper flavor, go beyond simply browning ground beef — fry it long enough to get a little crisped-up edge for extra texture and flavor.
Any type of meaty stew is enhanced with extra cooking time. Consider cooking the meat a little bit longer once the sauce is added to let the ingredients come together.
Add a dash of salt to frying onions before adding the meat, then add a little more when the beef is cooking. Don't add salt to raw ground beef as it can dry out the meat.