How to Make It
Preheat broiler to HIGH. Arrange onion, serrano, and jalapeno on a rimmed baking sheet lined with aluminum foil. Broil 6 inches from the element until charred on all sides, turning occasionally, about 10 minutes. Place peppers and onion in a small bowl and cover with plastic wrap; let steam 10 minutes. Peel peppers; discard peels, stems, and seeds. Combine peppers, onion, garlic, 1/2 cup vegetable stock, and 1 can navy beans in a blender; blend until smooth.
Heat oil in a Dutch oven over medium-high. Add cumin, oregano, coriander, and cayenne; cook until fragrant, about 30 seconds. Add jackfruit and cook, stirring often, until beginning to brown, about 5 minutes. Add onion mixture, remaining 31/2 cups vegetable stock, remaining can of beans, and bay leaf; bring to a boil. Reduce heat to a simmer and cook until slightly reduced, about 15 minutes. Remove bay leaf and serve with garnishes.