Sprinkle fish fillets (or chicken pieces) liberally with salt and pepper. Coat the pieces with flour, patting them firmly, then shaking off excess flour. Heat 2 tablespoons of oil in a wide skillet (or 2 wide skillets), and cook the fish over medium-high heat for 3-4 minutes, until browned. Turn fish pieces over and cook another 3-4 minutes longer. Remove fish from skillet and keep warm. Add butter and heat until it turns a deep brown. Remove from heat and add juice of one fresh lemon. Pour over fish or chicken. This final sauce may be augmented with capers or minced garlic, if desired. Add them after butter before lemon juice.