Gray sole is a delicately flavored white fish. You can substitute flounder, turbot, or another type of sole.
Combine flour, salt, and pepper in a shallow bowl. Dredge fish fillets in flour mixture, coating both sides, and shake off excess.
Melt butter with oil in a saute pan over medium-high heat. When butter begins to foam, add fillets. Cook until golden brown, 2 to 3 minutes per side. Transfer each fillet to a serving plate.
Add almonds, parsley, zest, and 2 tablespoons juice to pan. Spoon over fillets, and serve with lemon wedges.