Grind the turkey or chicken breast in a meat grinder, or use ready-made minced poultry from the butcher.
Finely chop the onion.
In a bowl, combine the minced meat with 1 egg, the chopped onion, 3 tablespoons breadcrumbs, 2 teaspoons Dijon mustard, several splashes of Tabasco, 2 tablespoons parsley, salt, and pepper to taste.
Form the mixture into 4-6 medium to small meatballs.
Heat oil in a frying pan over medium heat.
Fry the meatballs, turning occasionally, until cooked through (internal temperature should reach 74°C / 165°F for poultry), roughly 10-15 minutes total.
Serve with boiled potatoes and a sauce (such as red wine sauce) or potato salad.