Just a quick note, in case it helps anyone. My white chocolate custard completely seized up on me. I’m talking a big lump of white chocolate on the bottom of the bowl with a soupy mess of yellow butter (probably mixed with cocoa butter) on the top. The more I tried to whisk it back together, the worse it got. I even tried with an electric hand mixer. Nothing was going to bring that back together. I remembered something I’d seen Alton Brown say: a little bit of water causes chocolate to seize, but more water will smooth it back out again. I thought, “Hm. Eggs contain water, and they’re also an emulsifier. I’m supposed to be adding the eggs to this anyway. Worst that can happen is I waste the eggs, because the butter and white chocolate are already a total loss.” So, I slowly beat the eggs into my awful, disgusting mess with the electric hand mixer. Tada! Smooth and creamy!