1. Heat 4 tablespoons butter in a small saucepan over medium until lightly browned, 3 to 5 minutes; set brown butter aside and let cool for 5 minutes.

2. In a medium saucepan, bring fish stock and vinegar to a boil over medium heat; cook until liquid is reduced to about 1 tablespoon. Reduce heat to low. Slowly whisk in remaining 8 tablespoons butter, 1 tablespoon at a time, fully incorporating after each addition. Remove from heat and slowly whisk in cooled brown butter until completely emulsified. Stir in capers, almonds, parsley, and 3/4 teaspoon salt; season with pepper. Set sauce aside and keep warm.

3. Heat olive oil in a large nonstick skillet over medium-high heat. Season scallops with salt and pepper. Add scallops to skillet and cook until a light-brown crust forms, about 2 minutes. Turn scallops and continue to cook until cooked through, 1 to 2 minutes more. Divide scallops evenly between serving plates; spoon sauce over scallops and serve immediately.