This is my approximate reconstruction of the recipe I cannot now locate. (Unlike the other recipes in this book, incidentally, this one is written for two servings only—for sentimental reasons.)
Heat oil and butter in a medium-sized skillet. Add tuna steaks and fry over medium heat until lightly browned on both sides. Remove from pan and set aside. Cover loosely with foil.
Sauté onions over low heat in same pan (adding more oil and butter if necessary) until softened but not brown. Stir in curry powder and lemon juice. Raise heat to high and deglaze pan with white wine. Simmer, stirring constantly, until liquid has reduced by about one-third. Lower heat, stir in crème fraîche or cream and return tuna steaks to pan. Cover pan and cook for about 5 minutes or until tuna is warmed through.
Place tuna on plates. Quickly stir in tomato paste and stir until well dissolved. Add salt and pepper to taste.
Pour sauce over tuna, dividing onions equally between the plates.
© 1992 Colman Andrews. All rights reserved.