Fish en Papillote with Beans, Greens & Anchovy Butter Sauce

Ingredients

• tablespoons butter, melted
• tablespoon anchovy paste
• tablespoon white wine vinegar
• tablespoon lemon juice
• garlic, grated
• tablespoon chopped parsley
• teaspoon black peppercorns
• Parchment paper, cut into 4 rectangles, about 13” x 9”
• A bit of olive oil, for brushing parchment
• pound cooked navy beans
• Several handfuls of greens , stems removed & cut into quarters
• green olives, pitted and chopped
• fillets of firm white-fleshed fish
• lemon, cut into thin slices