准备

Make the dressing

• In a liquid measuring cup, combine the canola and olive oils. Put the remaining dressing ingredients except the Parmigiano in a blender and blend until thoroughly combined. With the motor running on medium high, carefully pour in the oils in a slow, steady stream. The dressing will emulsify as soon as all of the oil is incorporated. Stop the motor, add the Parmigiano, and quickly blend to combine. (You can store the dressing, tightly covered, in the refrigerator for up to 3 days.)

Make the salad

• Cut the Parmigiano into small cubes and pulse it in a small food processor until coarsely grated to the consistency of large pieces of sand (not too fine). Alternatively, grate the cheese on the small round holes of a box grater.

  Put the lettuce in a large salad bowl. Drizzle a scant 1/3 cup of the dressing over the lettuce and toss well. Taste and add more dressing if necessary, a teaspoon or so at a time, until the leaves are nicely dressed. Add 1/4 cup of the Parmigiano and toss well. Taste a leaf and add more cheese if you like or pass more at the table. Season to taste with salt and pepper. Add the croutons, toss well, and serve.

Leftover dressing is great on pasta or potato salad, or brushed on grilled chicken or fish.