1 small sweet potato
6 tablespoons olive oil, divided
Kosher salt, freshly ground pepper
mushrooms (either 1 Portobello, or half a box of crimini), optional
½ small zucchini
1 small onion finely chopped
¼ teaspoon crushed red pepper flakes
1 cup cooked quinoa (from about ½ uncooked)
¾ cup dried breadcrumbs
1½ teaspoons fresh lemon juice
4 English muffins, split, toasted Or bread of your choice
Guacamole, tomatoes, fresh onions and sprouts (for serving; optional)
Preheat oven to 350°.
Lightly prick the sweet potato all over with a fork; rub with 1 Tbsp. oil, then season with salt and pepper. Roast directly on oven rack until tender, 30–45 minutes. Let cool. Remove and discard skin; mash flesh with a fork. Set aside.
Remove stem from mushrooms, just use the caps. Pulse cap in a food processor until finely chopped.
Coarsely grate zucchini on the large holes of a box grater; gather up in a kitchen towel and squeeze out excess liquid.
Cook your quinoa separately and let cool.
Heat 1 Tbsp. oil in a medium skillet over low. Cook onions and red pepper flakes, stirring often, until onions are soft, about 2 minutes. Add mushroom and zucchini and cook, stirring occasionally, until vegetables begin to release their liquid but have not taken on any color, about 2 minutes. Transfer to a large bowl; mix in quinoa and season with salt and pepper. Let cool.
Add breadcrumbs, lemon juice, and about ¼ cup reserved mashed sweet potato to quinoa mixture and mix well. Taste and adjust seasoning with salt and pepper if needed. If mixture is too loose, add more sweet potato to bind.
Divide mixture into 4 portions and form into patties, pressing firmly together with your hands. Heat 2 Tbsp. oil in a medium skillet over medium and cook 2 patties until golden brown, about 2 minutes per side; season with salt and pepper. Repeat with remaining 2 Tbsp. oil and 2 patties.
Tip: Patties can be made 3 days ahead. Cover and chill.