12 large sea scallops (preferably dry-packed), side muscle removed (about 1 1/2 pounds)
Kosher salt and freshly ground black pepper
2 cups shelled fresh peas (from about 1 1/2 pounds pods) or frozen peas
3 ounces bacon (about 3 slices), cut crosswise into 1/3–inch strips
1 medium shallot, cut crosswise into thin rings
1 1/2 teaspoons fresh lemon juice
1 tablespoon (or more) olive oil
3 tablespoons mint leaves, coarsely chopped, divided
Place scallops on a paper towel-lined plate and pat very dry with additional paper towels. Season both sides with 1/4 tsp. salt and 1/4 tsp. pepper total.
Bring 1 cup water to a boil, covered, in a small pot. Add peas and 1/2 tsp. salt; cook until peas are bright green and tender, about 2 minutes for fresh and 4 minutes for frozen. Drain peas through a strainer set over a bowl; reserve cooking liquid.
Meanwhile, add bacon to a large skillet and heat over medium-high. Cook bacon, stirring occasionally, until fat starts to render, about 3 minutes. Add shallot and cook, stirring, until softened and lightly browned and bacon is crisp, about 3 minutes more. Using a slotted spoon, transfer bacon and shallot to a small bowl, reserving fat in skillet. Add 1/2 cup cooked peas to bacon mixture.
Purée lemon juice, 1/8 tsp. salt, 1/8 tsp. pepper, the remaining 1 1/2 cups peas, and 1/2 cup reserved pea cooking liquid in a blender. Add oil and pureé until smooth. Add 2 Tbsp. mint leaves and pureé until just combined but pieces of mint are still visible. Divide pea purée among 4 plates.
Heat skillet with reserved fat over high until just barely smoking. Working in batches and adding more oil if necessary, sear scallops until a golden brown crust has formed and scallop releases from skillet, about 3 minutes per side. Top pea purée with scallops and bacon-pea mixture, then sprinkle with remaining 1 Tbsp. mint.