2 tablespoons olive oil ( plus more for drizzling), 3/4 cup sour cream, 2 teaspoons chopped chipotle in adobo sauce–plus 2 teaspoons adobo sauce, 1 lb sweet potatoes, 1 1/4 cup panko breadcrumbs, 1 cup sliced red onion, 1 teaspoon grated lime zest, 3 tablespoon fresh lime juice, 2 cups shredded green cabbage, 1 can (15 ounces) refried beans–warmed, Toasted hamburger buns or brioche buns, pickles.

1. Preheat oven to 425° F. Drizzle a baking sheet with oil. 2. Whisk together sour cream, chipotle and sauce; season with salt. Transfer 2/3 cup mixture to another bowl; set aside. 3. Scrub sweet potatoes and cut into 1/4″ rounds; add to remaining mixture. In a shallow dish, toss panko with oil; season to taste. Coat both sides of potatoes in panko, pressing to adhere; transfer to baking sheet. 4. Roast, flipping once, until golden and crisp, 30 to 35 minutes. Toss onion with lime zest and juice. Let stand 10 minutes, then stir in cabbage; season to taste. 5. Spread beans over bottoms of buns. Top with cabbage and sweet-potato rounds. Spread reserved sour-cream mixture over top halves of buns; serve with pickles.