David Lebovitz's recipe: orange marmelade, lemon juice, gin, Grand Marnier or Cointreau (I used the latter), orange twist for garnish. Muddle the marmelade in the lemon juice, then shake with the rest. The result is much what you'd expect: an orangey martini.
I do take issue with Lebovitz on some of his awkward measurements. 1.75 ounces of gin - seriously? It was a little better when I doubled it for two drinks but 3.5 is still unusual. Fortunately, I have the graded measuring cup for the job but most people wouldn't.