Preheat oven to 375°F; lightly grease a large, rimmed baking sheet.
Warm oil in a large skillet over medium-high heat. Add celery and onion and cook, stirring often, until softened, 3 to 5 minutes. Add garlic and sauté 1 minute longer.
Pour beans into a large bowl and use a fork to mash into a thick paste. Scrape vegetables from skillet into bowl. Stir in egg, cumin and bread crumbs. Season with salt and pepper and use your hands to form 4 patties. Place on baking sheet and bake until firm and set, about 10 minutes on each side.