Arrange ramekins in a roasting pan and bake in a
water bath until custards are just set around edge but centers wobble when pan is gently shaken, 30 to 35 minutes. Cool custards in water bath 20 minutes, then remove from pan and chill, uncovered, at least 4 hours. (Custards will set completely as they chill.) Sprinkle about 1 teaspoon turbinado sugar evenly over each custard, then move blowtorch flame evenly back and forth close to sugar until sugar is caramelized. Let stand until caramel is hardened, 3 to 5 minutes.