Step 1

Rinse the potatoes and dice them into approximate 1 1/2 inch pieces. Place in a large (6-8 quart) stockpot and cover with water by 2 inches. Add 1 tablespoon kosher salt.

Step 2

Cover and bring the potatoes to a boil. Uncover and cook for 10 minutes, until the potatoes are tender.

Step 3

While the potatoes cook, make the dressing. Soak the shallot and garlic in the vinegar for 5 minutes to soften their "bite," then stir them with the tahini, brown sugar, and both mustards in a bowl large enough to hold the potatoes.

Step 4

Drain the potatoes, reserving 1/2 cup cooking water. Mix the potatoes into the dressing, adding the reserved cooking water 2-3 tablespoons at a time. Mix in the scallions.

Step 5

Taste the potatoes and sprinkle with additional salt, if desired. Serve warm, at room temperature, or chilled.

Step 6

Make it ahead! The potato salad can be made up to 1 day in advance. Refrigerate in a covered container until ready to serve.