makes 1 cup; adapted from Rose Bakery's book, Breakfast Lunch Tea
Pour cream into heavy bottomed saucepan, add vanilla bean and seeds (if you're using vanilla extract, don't add it yet, wait until after cooking) and bring to a boil over moderately high heat. Remove pan from heat, cover, and let steep 10 minutes.
In bowl, whisk egg yolks with the sugar until they are thickened and a rich yellow color, a couple minutes. While whisking constantly, add a bit of the warm cream to the yolks, then add that mixture back to the pot of warm cream and return to stovetop, set to a low heat (you do not want to scramble the eggs, so stir constantly and keep heat low-low-low). Stir constantly with a wooden spoon until custard coats the back of the spoon (run your finger across it; it will leave a track when you've cooked long enough), about 4–6 minutes. Remove from heat and strain through a mesh strainer into a glass jar. Cool to room temperature, cover with lid or plastic, and refrigerate.