Tuesday, February 23, 2016

Lemon Curd in the KitchenAid Precise Heat Bowl

You might have read my coffee ice cream recipe where I used the KitchenAid Precise Heat Bowl to cook the custard. That bowl is the latest KitchenAid attachment I bought, and of course I'm going crazy trying different recipes.

This curd is the first thing I tried, and I've made it several times since. It's really good.

The reason I chose curd as my first experiment with the bowl is that temperature is really important - it thickens at about 170 degrees ... but if you let the temperature get too high, you end up with lemony scrambled eggs. When I make lemon curd on the stove, I just stir and watch. It works most of the time.

But since the Precise Heat Bowl heats precisely, I figured that I could just let it do its thing, and the curd wouldn't overcook.

It all went swimmingly until I had the bright idea that I wanted to use the stand mixer to stir the curd while it heated, just like I'd stir curd by hand on the stove. First, I decided to use the paddle attachment. Oops. With liquid, it was quite splashy, even a the lowest speed. So I got smarter and used the whisk attachment. That worked much better.

I tried a couple different heating/stirring schemes before I figured out the fastest, easiest thing to do. One problem I ran into was that stirring lowered the temperature - or at least it thwarted the speed that the mixture heated, so it took a looooong time to get up to 170 degrees. For one thing, you can't have the lid on the bowl when stirring, so heat isn't retained. And I think the stirring itself was cooling the mixture.

Then I ran into another weird thing. According to the "back of the spoon" test, the curd was cooked. But when I tested with a thermometer, it wasn't at 170 degrees. I knew it wasn't the thermometer - I use a Thermapen and that sucker is always right.

I had to think about that for a while. I wondered if my bowl was defective. I thought about it some more.

And then I realized that the bowl doesn't measure the temperature in the center of the mix - it measures the temperature at the edges of the bowl. But that's not a bad thing, really, particularly when making curd. Just like when you're making ice cream and the paddle is scraping the frozen mix from the edges of the bowl to the center, when you use the precise heat bowl and stir, you're pulling the warmer mixture to the center. It cools off a bit there, but that's fine.

On the other hand, if you need the entire mixture at the same temperature, you could simply put the cover on and don't stir - or just stir once in a while by hand - until it all reaches the same temperature. But for curd, it doesn't all need to be the same temperature at the same time, and I have to say that just setting it up and letting it go was danged easy.


What? Sometimes my inner cartoon character needs to have a word.

Lemon Curd

1 stick unsalted butter at room temperature
1 cup sugar
1/4 teaspoon salt
4 whole eggs
2 teaspoons very fine lemon zest
3/4 cup lemon juice (I used Meyer lemons)

Put the butter, sugar, and salt in the Precise Heating Bowl attached to your stand mixer. Beat with paddle attachment until light and fluffy.

Add the eggs one at a time, beating until well combined each time. Add the juice and zest and mix until combined.

Remove the paddle attachment and put the cover on the precise heating bowl (you can leave it on the mixer or not, as desired.

Set the heat to 165 degrees. Stir a few times during the heating process, making sure to scrape the bottom and sides of the bowl.

When the temperature reaches 165 degrees, remove the cover. give the mixture another stir, and attach the whip attachment to the mixer. Set the temperature to 170 degrees and then timer for 5 minutes. Turn the mixer on to the lowest speed.

The temperature will initially go down a bit, but will slowly rise to 170 degrees at which point the bowl will start counting down the time.

When the time is up, transfer the curd to a container. Let it come to room temperature, then refrigerate.

Note: I usually strain curd to make sure there are no lumps, but this was silky smooth. You can strain it, if you like.