Step 1

Prep your green things: Trim roots and leggy stalks from 1 bunch mature spinach (9–12 oz.). Wash well and spin or pat dry; coarsely chop. Coarsely chop leaves and tender stems from 1 small bunch dill to make ½ cup. Set a few tender sprigs aside for serving; reserve remaining dill for another use.

Step 2

Bring 8 cups water to a boil in a medium Dutch oven or other heavy pot. Add 1 Tbsp. plus 1½ tsp. vegetable bouillon paste (preferably Better Than Bouillon) or 4 cubes bouillon (or follow the package instructions) and whisk to dissolve. (Alternatively, you can heat 8 cups vegetable stock or low-sodium vegetable broth if you prefer). Add 10 oz. cheese, spinach, or mushroom tortellini and cook 3 minutes (or according to package directions), then remove from heat. Using a spider, slotted spoon, or fine-mesh sieve, divide among bowls.

Step 3

Cut 1 lemon in half and squeeze juice through your hand or a fine-mesh sieve into a small bowl. You should have ¼ cup; repeat with another lemon if you need a little more juice.

Step 4

Whisk lemon juice, 4 large eggs, and 1 tsp. freshly ground black pepper in a medium bowl or large measuring glass to combine.

Step 5

Return broth to a gentle simmer. Scoop out about 1 cup and very gradually drizzle into egg mixture, whisking constantly. (This step, called tempering, warms up the delicate eggs slowly so that they don’t scramble when you add them to the rest of the hot broth.) The egg mixture should be quite warm to the touch—if not, whisk in more broth.

Step 6

Whisking constantly, gradually pour warm egg mixture into broth in pot. Cook, whisking often, over medium heat, until slightly thickened, 5–7 minutes. (Do not let broth come to a full boil.) Taste and season with kosher salt and more pepper if needed. If your broth is really salty, you might need to add a bit of water to dilute the soup.

Step 7

Remove from heat and add spinach and chopped dill (the spinach will wilt immediately.)

Step 8

Ladle broth into bowls with tortellini. Drizzle with extra-virgin olive oil and shave or finely grate Parmesan over. Sprinkle with a little pepper and top with remaining reserved dill sprigs.

Step 9

Do ahead: Tortellini can be cooked 2 days ahead. Toss in an airtight container with a little oil to keep from sticking. Cover and chill. Broth can be made 2 days ahead. Let cool; cover and chill. Reheat very gently, stirring constantly to re-emulsify (it may separate in the fridge), before ladling over tortellini.