This German classic makes mashed potatoes redundant, which leaves more room for the candied sweet potatoes.
Melt the butter over medium heat in a wide skillet. Add onion and cook, stirring often, until it is limp and starting to turn gold. Stir in the celery so it’s covered with butter and remove pan from the heat.
Combine pan contents with remaining ingredients; mix thoroughly, then taste and adjust seasonings. Old recipes call for as much as three times the amount of butter given here- and cream in the potatoes! – so feel free to add to taste.