Preparation

1. Heat 2 tablespoons of the oil in the HexClad 12” Hybrid Pan over medium. Add panko and cook, stirring often, until lightly golden, about 5 minutes. Season with salt and pepper. Transfer to a bowl and let cool.
2. Increase heat to medium-high and add the remaining 2 tablespoons of oil. Finely chop half the red onion and add it to the pan. Season with salt and cook, stirring occasionally, until softened and beginning to turn golden, about 5 to 7 minutes. Stir in the sweet potato and tomato paste and season with salt and pepper. Cook, stirring often, until everything has started to caramelize, about 8 to 10 minutes. Add cumin seed and garlic and cook, stirring frequently, until fragrant, about 1 to 2 minutes more.
3. Transfer mixture to a large bowl and add the beans and add ½ cup of the toasted panko. Mash everything together with a potato masher or clean hands, leaving some whole bean pieces intact. Season with salt and pepper, then stir in egg to combine. Form mixture into 4 patties using a ½ cup measuring cup. Coat each patty in remaining panko and place on a parchment lined baking sheet. Patties can be cooked right away or covered and chilled for up to 1 day or frozen up to 1 month.
4. Meanwhile, thinly slice the remaining half of the onion and toss with vinegar, 1 teaspoon salt, and sugar. Set aside.
5. Heat the HexClad Double Burner Griddle over medium heat. Add buns, cut side down, and cook until lightly toasted, 1 to 2 minutes. Transfer to a plate. 
6. Brush griddle with oil. Add the veggie burgers and cook, flipping once, until golden brown and cooked through, 2 to 3 minutes per side. If using cheese, cook the patty on one side, flip and add the cheese. Place an inverted metal bowl over the patties to melt the cheese.
7. To serve, spread avocado lime sauce over the cut side of the bottom bun, add the spring greens, veggie burger, snap peas, and pickled red onions. Season with salt and pepper and serve with more avocado lime sauce.