This has become one of my favorite salads. If you like you can also quickly sauté  the tat soi with the scallions, toss in the dressing and serve as a cooked side.

1 bunch tat soi or other similar greens, chopped
2 – 3 scallions, chopped
2 T lemon juice or white wine vinegar
1 T Dijon or other mustard
salt and pepper, to taste
4 T extra-virgin olive oil

1. Combine tat soi and scallions. In a bowl combine lemon juice, mustard, salt, and pepper. Whisk until smooth. Add oil and whisk until emulsified. Pour over tat soi and toss to combine.