Combine the olive oil, lemon juice, rice vinegar, chervil, shallots, and salt and pepper in a small bowl or container. Stir or shake to blend well.
Notes
Not familiar with tarragon? It looks like very feathery carrot tops. The color is pale green (don’t buy it if it’s yellowing). It’s fairly fragile, and hard to get outside of its spring growing season, so when you have it, use it. Also its delicate flavor doesn’t stand up all that well to heat, so if you are using it in a cooked preparation use it at the very end, or more as a garnish.