Spring Onion Oil (Mỡ Hành)

February 7, 2025

Spring Onion Oil (Mỡ Hành) © kvalifood.com

Mỡ hành - literally “fat/oil onion” - is one of the quiet workhorses of Vietnamese cooking. It sits alongside nước chấm and sate as a condiment that shows up constantly but rarely gets its own spotlight. The idea is dead simple: hot oil meets chopped spring onions, and the result is a fragrant, glistening sauce that adds richness, colour, and a gentle allium punch to whatever it touches.

It takes about two minutes to make, keeps for several days, and the ingredient cost is negligible. That combination of effort-to-reward is why it is considered an essential recipe for any Vietnamese cook.

Ingredients

2 tbsp peanut oil
1 cup spring onions, sliced finely; separate white from green
1 tsp fish sauce
1 tbsp shallots, sliced

Directions

Heat the peanut oil in a small pan until very hot.
Add the white parts of the spring onions and the sliced shallots. Fry for about 30 seconds until they start to sizzle and turn fragrant.
Add the green parts of the spring onions and stir. Pour in the fish sauce and cook for about 1 more minute.
Remove from heat and let it cool.

Notes

Keeps for about 5 days in the refrigerator.
A classic topping for cơm tấm (broken rice) and steamed or poached chicken.
Separating the white and green parts matters - the whites need more heat, while the greens just need a quick flash.

In Vietnamese kitchens, mỡ hành exists because it solves a practical problem. Many Vietnamese dishes - steamed chicken, plain rice, rice noodles - are deliberately mild on their own, designed to be finished at the table. Mỡ hành gives those dishes their final layer of flavour and that characteristic glossy sheen you see on plates of cơm tấm at street stalls. It is not a dipping sauce; it is a finishing drizzle, applied after cooking.

You will find it on or alongside:

Cơm tấm (broken rice) - arguably the dish most associated with mỡ hành, especially in southern Vietnam
Gà luộc / gà hấp (boiled or steamed chicken) - the scallion oil is spooned directly over the sliced chicken
Xôi mặn (savoury sticky rice)
Bánh cuốn (steamed rice rolls)
Bánh bèo, bánh khọt (small steamed or pan-fried rice cakes)
Bún thịt nướng (grilled pork vermicelli)
Bắp nướng (grilled corn)
Plain steamed rice, congee, or any simple noodle dish that needs a lift