Step 1

Steam potatoes, covered, in a metal steamer basket set in a large pot over boiling water until tender, 20–30 minutes, depending on size. Transfer to a plate and let cool.

Step 2

Meanwhile, cook eggs in a large saucepan of boiling water until whites are set and yolks are still slightly soft, 7 minutes. Drain; transfer eggs to a bowl of ice water and chill until cold. Drain and peel; set eggs aside.

Step 3

Toast mustard seeds in a dry small skillet over medium-low heat, tossing constantly, until seeds start to pop, about 1 minute. Transfer to a small bowl (be ready with bowl; once seeds get going, it’s chaos).

Step 4

Whisk vinegar, mustard, and honey in a large bowl. Whisking constantly, gradually add oil; whisk until emulsified. Season with salt and pepper. Set 3 Tbsp. vinaigrette aside for drizzling.

Step 5

Halve potatoes and add to bowl with vinaigrette. Add parsley and toss to coat; season with salt and pepper. Transfer to a platter. Halve reserved eggs and tuck in between potatoes. Drizzle with reserved vinaigrette. Top with pickles, chives, and toasted mustard seeds.

Step 6

Do Ahead: Eggs can be boiled 1 day ahead; drain, cover, and chill. Peel just before using. Vinaigrette can be made 3 days ahead; cover and chill.