Step 1: Make the Pickled Corn

1. Shuck 2 medium corn cobs and remove silk. In a shallow bowl, slice off the top 2/3 of the kernels using a serrated knife with a downward motion.
2. Add ½ finely diced shallot, 2 Tbsp champagne vinegar, and ½ tsp fine sea salt to the corn; toss to combine.
3. Cover and chill for at least 1 hour (up to 1 week), stirring occasionally.

Tip: Use a shallow bowl to catch kernels; stir periodically to ensure even pickling.

Step 2: Prep the Leeks

1. Slice 3 medium leeks in half lengthwise, then cut the white and light green parts into ½-inch thick pieces.
2. Place leeks in a large bowl, cover with cool water, and let stand for 5 minutes, swishing occasionally to remove dirt. Drain before using.

Tip: Rinse leeks thoroughly, as dirt often hides between layers; pat dry to avoid excess water.

Step 3: Cook the Vegetables

1. In a large saucepan or soup pot, melt 2 Tbsp butter over medium heat.
2. Add drained leeks and 1 medium chopped Yukon Gold potato; cook, stirring, until softened, about 5 minutes.
3. Add 1¼ lb chopped zucchini and cook, stirring occasionally, until fairly soft, about 5 minutes.

Tip: Chop vegetables uniformly for even cooking; stir frequently to prevent sticking.

Step 4: Simmer the Soup

1. Add ½ tsp salt, a few grinds of black pepper, and 4 cups water (just enough to cover vegetables).
2. Increase heat to bring to a boil, then reduce to medium-low and simmer, partially covered, for 15 minutes until zucchini and potato are very soft.
3. Remove from heat and cool to room temperature, about 15–20 minutes.

Tip: Don’t overfill with water to maintain flavor; cool soup slightly before blending for safety.

Step 5: Blanch the Basil

1. Bring a medium saucepan of water to a boil and prepare an ice water bath.
2. Reserve a few basil sprigs for garnish; add remaining basil leaves (2–3 cups) to boiling water.
3. Cook for 20 seconds until bright green, then transfer to the ice bath with a slotted spoon. Swish until cold, then squeeze dry.

Tip: Blanching basil preserves its vibrant color; squeeze gently to remove excess water without bruising.

Step 6: Blend the Soup

1. Using a slotted spoon, transfer the soup solids to a blender or food processor (work in batches if needed).
2. Add blanched basil and a small amount of cooled soup liquid. Puree until smooth, adding more liquid as needed for a creamy consistency.
3. Blend in 2 Tbsp lemon juice; taste and adjust with more lemon, salt, or pepper. Optionally, blend in 2–3 Tbsp crème fraîche for extra creaminess.

Tip: Blend carefully to avoid hot splashes; adjust liquid for desired thickness.

Step 7: Serve

1. Return soup to the pot and warm over medium heat, stirring occasionally.
2. Ladle into bowls, swirl with a dollop of crème fraîche, top with a scoop of pickled corn, and garnish with basil sprigs.
3. Serve immediately.

Tip: Warm gently to avoid overheating; serve with extra pickled corn on the side for added crunch.