Preheat your oven to 300 degrees.

In a medium bowl, whisk the egg yolks, sugar, and vanilla extract together until the mixture is thick and creamy.

In a sauce pan, heat the half and half and evaporated milk until it almost comes to a boil.

Remove the sauce pan from the heat immediately and stir in the corn starch. Stir until well combined.

Add the egg yolk, sugar, and vanilla extract mixture and whisk until well combined.

Pour this mixture into the top pan of a double boiler. If you don't have a double boiler, you can set a glass bowl on top of a sauce pan that has a couple of inches of simmering (not boiling) water. In this case, you would pour the mixture into the glass bowl.

Allow the mixture to simmer for 3-5 minutes.

Remove the mixture from the heat and pour into a shallow baking dish. You can use a pie dish, tart dish, or individual sized crème brûlée dishes.

Bake at 300 degrees for 30 minutes.

Remove from the oven and allow to cool completely to room temperature.

Once it has reached room temperature, transfer to your refrigerator and allow it to chill for at least two hours. You can even allow it to chill overnight.

In a small bowl, combine the white sugar and brown sugar and sprinkle evenly over the top of the chilled custard.

Use a culinary torch to melt the sugar until it starts to caramelize and form a crust. It will be light brown in color.

If you do not have a culinary torch, you can also use your oven that is set to broil (550 degrees).

Once your oven is ready, place the custard in the oven for approximately 2 minutes. You will want to keep a close eye on this so that the sugar does not burn.

As soon as you see the sugar melt and start to caramelize, you will want to remove it from the oven.

If you are using this oven method, you will then want to return the crème brûlées back to the refrigerator to allow the custard to set again. If you skip this step, the custard will be runny because it has gotten hot in the oven.