Blanch the broccoli in boiling water with a pinch of salt, then chop and freeze for storage.

Wash and peel the potato, then slice it thinly.

Wash and slice the onion thinly.

Heat a pan with butter and sauté the sliced potato and onion until partially cooked.

Blend the broccoli, potato, and onion in a mixer. Add a little milk if blending is difficult.

Transfer the blended mixture to a pot.

Add milk to the pot and mix well over medium-low heat.