Preheat your oven to 400°F (204°C). Position two racks so you can fit both baking sheets in at once. Then, line two baking sheets with foil, parchment, or a silicone mat.

Drain the beans and spread them on one of the prepared baking sheets.

Wipe the mushrooms with a damp paper towel. Remove tough stems, then roughly chop.

Roughly chop up the carrot, broccoli, and onion into ½-inch pieces.

Add the mushrooms, chopped vegetables, garlic, olive oil, smoked paprika, chili powder, salt, and pepper to the food processor. Pulse until coarsely ground (10 to 20 times). Put the ground vegetable mixture on the second baking sheet and pat it into a thin, even layer.

Slide both baking sheets (beans and veggies) into the preheated oven.

Roast the beans until dry with slightly split skins, about 15 minutes.

Roast the vegetables until they look dry and toasted, about 30 minutes. Stir them a few times and press them back into a thin layer to prevent the outer edges from over-browning.

Let both the roasted vegetables and beans cool on the counter.

While the beans and vegetables roast, rinse the food processor bowl and pat it dry.

Place the walnuts, spinach, and fresh parsley into the clean food processor bowl. Pulse briefly until roughly chopped, resembling the size of breadcrumbs.

Add cooled beans and pulse 5 to 10 times until the beans look crumbly with large crumbs.

Add the roasted vegetables, breadcrumbs, eggs, and tomato paste. Pulse until everything is just combined. You want to keep some texture and avoid over-processing it into a smooth paste.

Transfer the mixture to a bowl and gently fold in the cooked rice.

Divide the veggie burger mixture into 8 equal portions (each portion should be about 3 ¼ ounces or 90 grams). Form each portion into a patty that’s about ½-inch thick.

Place a skillet over medium-low heat and add oil (about 1 tablespoon for 4 burgers). Carefully place the patties in the skillet and cook on each side for 4 to 6 minutes until heated through, firm, and browned. As you flip them, a few bits might fall. Gently press any loose bits back into the sides of the patties.