Translation:I recommend pork with dumplings and sauerkraut.
That's not how you normally say it in English I suppose - the dumpling is not actually just one piece in this case.
In a sentence like this, it just means the kind of food, doesn't say anything about its quantity. The singular in dish names and recipes might have something to do with the fact that the common Czech "knedlík" is cooked whole, then sliced, unlike the dishes that are usually called "dumplings" in English. For dishes that are cooked in smaller pieces, like the sweet "knedlíky" filled with fruit, you would always use the plural, unless you are talking about one single piece.
Could you say "with dumpling" (no "a"), considering it uncountable here? After all we are not counting dumplings but slices.
But we call each slice "1 knedlík" so I would do the same in the English translation.
Although for the "s knedlíkem" that does not really make sense so I would stay with the plural. If you can show it is used as uncountable by some reputable sources, we could add it, but most will be people who use Google Translator to translate their menus and get things like "candle sauce with cranberry target".