Vegetarian Sliders with Black Beans, Chard & Poblanos

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.

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. 

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.

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.

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. 

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. 

Serve the patties in buns, topped with the reserved peppers, pickled onion and feta. Sprinkle with more Creole seasoning, if desired.