It took me a few tries to get the hang of cooking with an Anova sous-vide immersion circulator, but now I love it.
Here's how you cook something sous vide (under vacuum) style – put meat or vegetables (along with spices and fat) into a plastic bag with the air removed, and submerse it in a controlled temperature water bath for a couple of hours of more. Remove the food and sear it in a pan or with a torch. Sous vide cooks food gently and evenly all the way through. I made pork tenderloin using this Nom Nom Paleo recipe and it was incredibly tender.
The Anova has a Bluetooth radio. You can sync it to an iPhone, call up a recipe, and press a button on the app to start a temperature cycle. But I usually just use the buttons on the Anova device itself to set the temperature. When I make the pork tenderloin, I set the temperature to 135F and let it run for about 5 or 6 hours (the Nom Nom recipe calls for a minimum of 2 hours). I have learned that it's better to cook something for at least 3 or 4 hours. That way, the food is completely cooked, yet it is still tender.
I'd love to hear your favorite sous vide recipes and tips in the comments.