The espresso martini is one of those cocktails that typically goes horribly wrong. But making a good version isn't hard, says Milk Street Editorial Director JM Hirsch. Start with good espresso, leave the sugar out (and use Kahlúa instead), go ahead and use mid-shelf vodka and the secret ingredient? Salt. Just as it does in cooking, salt balances the flavor of cocktails, and just a few granules go a long way in this rich, boozy drink that's so good you'll find yourself reaching for another before you've finished your first.