After the slices were done toasting, I spread butter and mustard on each one.
I have to be honest with you, reader, I read the recipe incorrectly here. I thought Garten recommended spreading half the slice with butter and half with mustard, which made for a cool picture but was definitely not the case.
What the "Barefoot Contessa" star actually wants you to do is spread each slice with ½ tablespoon of butter and ½ teaspoon of mustard.
Thankfully I really like mustard, so the extra flavor didn't put me off. But next time I'll wait to read the recipe until after I've had a cup of coffee.
Also, a quick pro tip: Be sure to take your butter out of the fridge before you begin cooking your eggs. That way it'll reach room temperature by the time you're ready to prep your toast, making it far easier to spread across the bread.