3 leeks, white and pale green parts only, tough outer layer removed
2 Tbsp. extra-virgin olive oil
1 lb. baby creamer (Yukon Gold) potatoes, halved (quartered if larger than 1 1/2" in diameter)
2 tsp. kosher salt, divided
1 1/2 tsp. freshly ground black pepper, plus more
1 cup pure clam juice
2 bay leaves
1 lb. monkfish cut into 2x1" pieces
1 cup heavy cream
1 (10-oz.) bag frozen sweet peas, thawed
1 Tbsp. fresh lemon juice
Pea shoots or sprouts for garnish
Cut leeks into 1/4" rounds. Rinse, tossing with hands so that leeks separate into individual rings, and drain thoroughly. Transfer to a medium pot. Add oil and toss to coat. Cover pot and cook over medium heat until leeks begin to soften, 5–6 minutes.
Add potatoes, 1 tsp. kosher salt, and 1 1/2 tsp. pepper and stir to combine.
Add kelp cubes, clam juice, bay leaves, and 2 cups water and bring to a boil.
Reduce heat to medium-low and cook, uncovered, until potatoes are fork-tender, 10–12 minutes.
Season monkfish with remaining 1 tsp. kosher salt.
Add to pot along with cream and peas and stir to combine. Cook, stirring occasionally, until monkfish opaque, 3–4 minutes.
Remove from heat and stir in lemon juice.
Top with pea shoots, basil, and lemon zest. Season with sea salt and a generous amount of pepper.