Preheat the oven to 300 degrees F.
In the bowl of an electric mixer fitted with the paddle attachment, mix the egg, egg yolks, and 1/2 cup of the sugar together on low speed until just combined. Meanwhile, scald the cream in a small saucepan until it's very hot to the touch but not boiled. With the mixer on low speed, slowly add the cream to the eggs. Add the vanilla and orange liqueur and pour into 6 to 8-ounce ramekins until almost full.
Place the ramekins in a baking pan and carefully pour boiling water into the pan to come halfway up the sides of the ramekins. Bake for 35 to 40 minutes, until the custards are set when gently shaken. Remove the custards from the water bath, cool to room temperature, and refrigerate until firm.
To serve, spread 1 tablespoon of sugar evenly on the top of each ramekin and heat with a kitchen blowtorch until the sugar carmelizes evenly. Allow to sit at room temperature for a minute until the caramelized sugar hardens.
Propane gas torches are highly flammable and should be kept away from heat, open flame, and prolonged exposure to sunlight. They should only be used in well-ventilated areas. When lighting a propane gas torch, place the torch on a flat, steady surface, facing away from you. Light the match or lighter and then open the gas valve. Light the gas jet, and blow out the match. Always turn off the burner valve to "finger tight" when finished using the torch. Children should never use a propane gas torch without adult supervision.
» Metric Converter