If using ring bologna: Remove any strings or clips off the ends. Cut the bologna into 4 sections for easier handling. Slit one side of each section lengthwise and remove the casing.
Install discs onto the front of the meat grinder for a fairly small grind and grind the bologna into the glass dish. After digging the rest of the bologna out of the grinder, dump the bologna into the mixing bowl.
Finely-chop the sweet pickles till you have about 1/2 cup, and then do the same with the slices of onion. Add the chopped pickle and onion to the ground bologna in the mixing bowl, then add the mayonnaise and mustard and mix it all together till it’s smooth. Taste it, adding some salt and pepper to punch up the flavor if necessary.
Transfer it to the storage bowl and refrigerate the spread until it’s ice cold.
Use a fork to put a layer of spread about 3/8″ thick (my kids like it about 1/2″ thick on a slice of white bread, then close with another slice.
Serve with kettle-cooked potato chips or steaming-hot French fries.
Serving Size 4 tablespoons