-Cover 2# of whole potatoes with water by 1 inch in a 3- to 4-quart saucepan, then bring to a boil with 1 tsp sea salt.
-Simmer, partially covered, until potatoes are tender, about 10 minutes, then drain.
-In a large bowl whisk together the following:
1/2 TBS Dijon mustard
1 TBS whole-grain mustard
2 TBS white-wine vinegar
1/2 tsp black pepper
1/2 teaspoon sea salt
-Then add 3 TBS olive oil in a slow stream, whisking until emulsified.
-When potatoes are just cool enough to handle, halve them, then add to vinaigrette.
-Stir in 2 TBS chopped basil and 1 TBS finely chopped rosemary.
-Serve warm or at room temperature.