Mustardy Potato Salad with Peas

1/2 cup extra virgin olive oil
3 tablespoons or more good wine vinegar
1 heaping tsp any mustard or 1/2 tsp or so dry mustard
1 to 2 tablespoons honey (optional)

Cut potatoes into bite-sized pieces. Put them in a pot with enough water to cover them and add a large pinch of salt. Bring to a boil, then lower the heat so the water bubbles gently. Cook the potatoes until tender but still firm and not all mushy, 15 minutes or so, depending on the potato. Drain, rinse in cold water for a minute, then drain again.

Shell peas and lightly steam until bright green, but still firm.

Combine all the vinaigrette ingredients in a blender and turn the machine on; a creamy emulsion will form within 30 seconds. Taste and add vinegar a teaspoon or two at a time until the balance tastes right to you. (This dressing is best made fresh but will keep, refrigerated, for a few days; bring it back to room temperature and whisk briefly before using.)

Toss the still-warm potatoes with the parsley, peas, and scallion. Add the vinaigrette until the mixture is as dressed as you like. Taste and adjust the seasoning, adding black pepper. Serve as is or refrigerate for an hour or so to chill the salad.