Custard Tips

I used to be terrified of making custard. The idea of mixing hot liquid with eggs just sounds like a sure-fire way to end up with egg-drop soup. So, whenever I had to make custard, I would drizzle the hot liquid into the egg yolks ever so slowly, and I used a hand mixer to make sure every hot droplet was distributed into the eggs as quickly as possible. After a couple of successful custards, though, I started getting complacent. I ditched the hand mixer for a whisk and started pouring faster and faster, until...

Yesterday, I totally screwed up a batch of custard. We're talking big time egg-drop soup, pieces-of-coagulated-protein-floating-in-liquid style screwed up. This wake-up call reminded me that cooking is a science, and it requires due attention and care.

That said, I decided to write up some points that I've learned, so you won't make the same mistakes.

The typical custard recipe has the following steps:
1. Heat the liquid (milk, cream, etc) with sugar and flavoring (ex. vanilla) until boiling.
2. Add the hot liquid to beaten egg yolks
3. Cook the mixture over the stove top until "thickened to coat the back of the spoon".

Step #1 is fairly straight forward.

The goal for step #2 is to incorporate the hot liquid into the egg yolks in as gentle and gradual a way as possible, so no bit of egg yolk gets overcooked.
- Add some sugar to the egg yolks before tempering with hot milk/cream. I think it helps to add the sugar to the egg yolks to create some insulation, especially when the pot is heavy and it's easy to slop more than you intended into the eggs.
- Start by slowly drizzling the hot liquid into the egg yolks and whisk frequently. Once half of the hot liquid has been mixed in, you can start pouring faster. 

The goal for step #3 is to increase the heat of the egg dairy mixture as gently and thoroughly as possible.
- Keep the heat low. Having the heat too high means the bottom will cook faster than the top, and you risk getting bits of egg stuck to the bottom of the pan.
- Use a silicon spatula, or something that will get into the corners. The unreachable regions in the corner of the pan will get too hot and solidify. Besides, a spatula is good for the next tip, which is...
- Stir, but not too much. When cooking custard, it's important to know when the custard has thickened. I made the mistake of using a whisk once. All that did was to create a lot of foam on top, which obscured my view of the actual custard. You want to stir it frequently to distribute the heat, but not so much that it foams up.

What's custard good for? Well, you can churn out the most rich and smooth ice cream, like the cookies and cream one below...