¼ cup nutritional yeast flakes or 3 tbsp. nutritional yeast
6 tbsp. extra-virgin olive oil, divided, plus more for serving
1 medium onion, finely chopped
¾ tsp. ground turmeric, divided
½ tsp. kosher salt, plus more
2 tbsp. yellow miso
4 garlic cloves, divided
1 15.5-oz. can chickpeas, rinsed, or 1½ cups cooked chickpeas
1 cup chickpea flour
½ tsp. baking powder
½ tsp. cayenne pepper
Freshly ground black pepper
½ cup finely chopped dill
⅓ cup plain Greek yogurt, plus more for serving
2 medium or 3 small celery stalks, thinly sliced on a diagonal
Place nutritional yeast in a small bowl or measuring cup and pour in ⅔ cup hot water. Stir to combine. Set aside.
Heat 2 tbsp. oil over medium in a medium pot. Add onion and ½ tsp. turmeric, season with salt, and cook while stirring often, until onion is softened and starting to brown around the edges, 5–7 minutes.
Add miso to the pot and finely grate in 3 garlic cloves. Cook, stirring and smashing down on miso constantly until miso starts to darken and stick to the bottom of the pot (similar to tomato paste), about 2 minutes. Add chickpeas and stir to coat. Carefully pour in golden liquid that’s floating atop the reserved soaking nutritional yeast, leaving as much of the sediment behind as you can (about ½ cup should remain but don’t stress if a little slips in); discard. Add 4 cups of water. Increase heat to high and bring to a boil. Reduce heat so the mixture is at a gentle simmer. Cover pot, and cook soup while you make the dumpling batter.
Whisk together the chickpea flour, baking powder, cayenne, ½ tsp. salt, and remaining ¼ tsp. turmeric. Season generously with black pepper. Add dill, ⅓ cup yogurt, 4 tbsp. oil, and 2 tsp. warm water, then finely grate in remaining garlic clove. Stir with a wooden spoon or rubber spatula until no dry spots remain. Your dough should be thick and sticky.
Using damp hands, form dough into 10 balls (the easiest way to do this is to divide the dough in half, then divide each half into 5 pieces); place on a cutting board as you go. Gently drop dumplings into soup, cover pot, and simmer gently, until dumplings puff dramatically and float to the surface (to check for doneness, take 1 out and cut it open; it should be cooked through—the interior should look soft and not too dense), 7–9 minutes. Add celery, being careful not to smush dumplings, and simmer, uncovered, until celery is crisp-tender, about 3 minutes. Season broth with salt and black pepper.
Ladle broth and dumplings into bowls and top with a dollop of yogurt. Drizzle with oil and season with more black pepper.