Preheat oven to 375ºF / 190ºC.
For the pea puree: Place the frozen peas into a small saucepan with enough water to cover. Bring to a boil and simmer over medium heat for 3-5 minutes until the peas are hot. Drain the peas well and place in a food processor with the mint and mascarpone. Pulse the mixture for about 1 minute until it's smooth, but still has a bit of texture. Season with salt and pepper to taste and set aside.
For the crispy pancetta: Lay out the pancetta in a single layer on a baking sheet covered with parchment paper. Place in the preheated oven for 10-12 minutes until crisp and brown. Remove to paper towel-lined plate and break apart into shards when cool enough to handle.
For the Jalapeño-Lime Butter: In a small saucepan melt butter, then add chili and lime zest and juice and stir together. Season with salt to taste. Set aside.
For the scallops: With a paring knife or your fingers, remove the small nub or “foot” from the edge of each scallop. Pat scallops completely dry and season on both sides with salt and pepper.
Heat a cast-iron skillet large enough to hold the scallops without crowding over medium-high. When pan is very hot, add oil (the oil should be nearly smoking). Add the scallops in a single layer with a little room between them and let them sear until they develop a deep brown crust, about 3-5 minutes. Don’t try to turn them until the crust forms. Turn off heat and flip scallops. Let the residual heat cook the other side. They should be just firm to the touch but not rubbery, 3-5 minutes.
To serve, place a dollop of the pea puree on each plate and top with the scallops. Drizzle over a spoonful of the butter and crumble half a slice of crispy pancetta on top of each scallop. (For appetizers, place small dollops of pea puree on a platter and top each with a scallop).