1, first, chop the portobello mushroom, chop the onion.

2, pour a little oil in the pot, the onion will be fried soft and sautéed.

3, the fried onions out of the pan, the pan into a little oil.

4, add the flour, medium heat fried flour fried until the flour is slightly brown.

5, pour in the milk, onions while cooking and stirring, cook for 4 minutes can be removed from the pot.