Vegetarian Sliders with Black Beans

Ingredients

• 1 cup boiling water
• 1 tablespoon honey
• ¾ teaspoon salt, divided
• 1 cup cider vinegar
• 1 small red onion, thinly sliced 
• 3 medium poblano peppers
• 1 tablespoon extra-virgin olive oil, divided
• 1 medium yellow onion, diced 
• 3 cloves garlic, minced
• 1 bunch chard, including stems, chopped (8 cups)
• 4 ½ cups cooked or canned (rinsed) black beans, patted dry
• 1 large egg, lightly beaten
• ½ cup fine dry whole-wheat breadcrumbs
• 2 teaspoons Creole seasoning, plus more for serving
• Cooking spray
• 16 slider buns, preferably whole-wheat, split and toasted
• 1 cup crumbled feta cheese

Directions

1. Combine boiling water, honey and 1/2 teaspoon salt in a heatproof bowl, stirring to dissolve the honey and salt. Stir in vinegar, then add red onion. Set aside.
2. Position rack in upper third of oven; preheat broiler to high. Place peppers on a baking sheet and broil, turning occasionally, until blackened on all sides, 12 to 15 minutes. Transfer to a bowl, cover with plastic wrap and let steam until cool enough to handle, about 15 minutes. Peel and seed the peppers. Slice or tear them into strips; set aside.
3. Meanwhile, heat 1 1/2 teaspoons oil in a large skillet over medium heat. Add yellow onion and cook, stirring occasionally, until soft and light golden brown, 3 to 5 minutes. Add garlic; cook, stirring occasionally, until fragrant and soft, 1 to 2 minutes. Scrape onto a plate.
4. Return the pan to medium heat and add the remaining 1 1/2 teaspoons oil and chard. Cook, stirring frequently and adding a splash of water if it starts to stick, until the stems are tender and any liquid has evaporated, 5 to 8 minutes. Scrape onto the plate and let cool, about 10 minutes.
5. Place beans in a large bowl and coarsely mash. Add the chard mixture, egg, breadcrumbs, Creole seasoning and the remaining 1/4 teaspoon salt; mix well.
6. Coat a baking sheet with cooking spray. Using about 1/3 cup to make each, portion the bean mixture into 16 patties, 1/2 inch thick, and place on the prepared baking sheet. Coat the patties lightly with cooking spray. Broil until browned and firm on top, 6 to 8 minutes. Flip the patties and coat the other side with cooking spray. Broil until browned, 4 to 6 minutes more.
7. Serve the patties in buns, topped with the reserved peppers, pickled onion and feta. Sprinkle with more Creole seasoning, if desired.