Mustardy Grilled Cabbage and Kielbasa

Prepare a grill for medium-high heat; oil grate with vegetable oil. Combine 1 lb. small red potatoes, halved, quartered if larger, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, ½ tsp. garlic powder, ½ tsp. smoked paprika, and 3 Tbsp. extra-virgin olive oil in a medium bowl, season generously with freshly ground pepper, and toss to combine. Scrape out onto a large sheet of foil; reserve bowl. Bring foil edges together to make a packet; crimp to seal tightly. Place on grate; cook potatoes until tender, 25–28 minutes.

Whisk 1 Tbsp. mayonnaise, 1 Tbsp. Dijon mustard, 1 Tbsp. whole grain mustard, and 1 Tbsp. extra-virgin olive oil in reserved bowl to combine. Rub mayonnaise mixture over 1 small head of savoy cabbage, cut through core into 2"–3"-thick wedges, working between leaves; reserve bowl. Grill cabbage, turning halfway through, until tender and both cut sides have deep brown marks, 7–9 minutes. Transfer to a platter.

Grill one 12-oz. kielbasa, quartered crosswise, then halved lengthwise, turning halfway through, until charred in spots, about 10 minutes. Transfer to same platter.

Whisk 3 Tbsp. apple cider vinegar, remaining 2 Tbsp. whole grain mustard, and remaining 1 tsp. extra-virgin olive oil in reserved bowl. Set dressing aside.

Arrange potatoes on top of kielbasa and cabbage. Drizzle reserved dressing over. Scatter torn dill on top and season with more pepper. To make without a grill: Preheat oven to 400°. Spread seasoned potatoes out on a foil-lined rimmed baking sheet; roast until just tender enough to pierce with a knife, 25–30 minutes. Remove from oven. Heat broiler. Add dressed cabbage and kielbasa to baking sheet with potatoes; broil, turning halfway through, until cabbage is tender and charred in spots and kielbasa is browned, 10–14 minutes.