Bring a large pot filled with salted water to a boil.
In the meantime, get your prep done. Slice the kielbasa sausages. Slice the onions and chop the chives.
Add pierogi to the pot with boiling water, cook for 3 minutes. When ready, drain and run briefly under cold water.
Heat oil and 1 tablespoon butter over medium high in a large skillet, add kielbasa and cook until golden brown. Remove from skillet.
Add the remaining butter and reduce heat to medium. Add onions and sauté for 3 minutes, or until soft and translucent.
Add pierogi, cook for 2 minutes. Finally, stir in kielbasa.
Top with chives and freshly ground black pepper.
