Combine milk and cream in a saucepan and bring to a boil. Meanwhile cut vanilla bean lengthwise in half and scrape seeds out bean using a small knife. Place vanilla bean and its content into cream mixture and remove from heat when it reached a boil. Allow to cool for 10 minutes.
Combine sugar and egg yolks in a bowl and whisk until smooth and well combined. While whisking gradually add boiled mixture.
Set ramekins into a roasting pan. Pour crème brûlée mixture into ramekins. Pour water into roasting pan until it comes halfway up sides of ramekins.
Place in oven and bake until center of ramekins no longer tremble. About 50 minutes to 70 minutes, depending on depth of ramekins used.
When cool enough to handle remove ramekins from roasting pan and place in refrigerator for several hours or overnight.
Remove from refrigerator and cover surface of crème brûlée with a thin even coating of granulated sugar.