Cook your sweet potato in the oven at 400°F for 20 minutes. Once the sweet potato has been cooked and peeled, let it cool a little.
Preheat the oven to 350°F.
Place the sweet potato flesh, chickpeas, barbecue sauce, salt, chili seasoning, and bread crumbs in a food processor. Mix until a homogeneous paste forms. You will probably need to scrape the side with a rubber spatula several times during the process.
When the preparation is homogeneous, separate into five equal parts and form patties with your hands. Freeze patties for at least 15 minutes to allow the mixture to firm up.
Place the patties on a baking sheet covered with parchment paper.
Cook in the oven for 30 minutes. Then let cool for about 5 minutes.
Meanwhile, prepare the toppings (tomatoes, lettuce, mayonnaise, pickles) and toast your hamburger buns.
Assemble the burgers by brushing the inside of each bun with mayonnaise, then stacking a cooked patty, lettuce leaf, pickles, and a tomato slice.