Heat a small skillet over medium heat until hot.

Add onion and celery.

Cook, stirring frequently, until vegetables begin to brown and stick to the bottom of the skillet, about 5 minutes.

Stir in garlic and vegetable broth; cook, scraping the bottom of the pan, until liquid has evaporated and onion is golden. Transfer to a large bowl.

Preheat the oven to 400°F.

Pulse almonds in a food processor until coarsely ground.

Add to the bowl with onion mixture.

Add remaining ingredients. Use your hands to mix and press the ingredients until they hold together.

With damp hands, form into 4 patties* about 4 1/2 inches in diameter and 3/4-inch thick. Place them on a parchment paper-lined baking sheet.

Bake 15 minutes, then flip burgers and continue to bake until lightly browned on other side, about 15 minutes longer.

*Forming neat veggie burgers: 
Dampen the inside of a 1/2-cup measuring cup and pack it with the burger mixture, pressing down firmly. Turn the cup over and shake it gently to release the mixture into the palm of your hand, then press down with your other hand until the patty is about 3/4-inch thick.

Freezing veggie burgers:
Cool cooked burgers and wrap individually in plastic wrap and then foil, or place them in individual resealable plastic bags, and freeze up to 6 months. To reheat, unwrap the burgers, place on a parchment paper-lined baking sheet and bake at 300°F until heated through, 20 to 25 minutes.