Melt butter and half of the olive oil in a skillet over medium heat, then add shallot and garlic. Add peas and stir. Cook for two minutes. Add white wine and reduce. Add cream and reduce. Season with salt and pepper, transfer to a food processor and blitz. Add the rest of the olive oil, then blitz again.
For the fish:
Wrap each fillet with three slices of pancetta around the middle. Place them seam side down on a plate.
Heat one tablespoon (15 milliliters) olive oil in a skillet over medium heat, add fish with the seam of the pancetta down, and then sear for two minutes on each side. Add garlic to pan. Deglaze with white wine, add lemon juice, and cook until wine reduces. Remove from heat, then stir in butter.
Serve fish over a bed of pea mash, then pour the wine sauce that’s left in the pan over top. Season with salt and pepper. Serve with lemon wedges.