I start by roughly chopping my leftover Halloween candy into small pieces so it melts evenly once the sandwich hits the skillet. Chocolate bars, peanut butter cups, and caramel-filled candies all work beautifully here. I avoid anything too hard, like lollipops, since they won't soften in time.
In a large bowl, I whisk together the eggs, milk, sugar, vanilla, cinnamon, and salt until everything looks smooth and pale yellow. This only takes about a minute, but it's the step that gives the toast its flavor, so I never rush through it.
Next, I lay out my bread slices and scatter the chopped candy evenly over half of them, then top with the remaining slices to form sandwiches. I press down gently so the candy stays put and doesn't spill out the sides once it starts melting.
I dip each candy sandwich into the egg mixture for just a few seconds per side. I don't let it soak too long, or the bread turns mushy and falls apart in the pan. A quick, even coating is really all you need here.
I melt butter in my skillet over medium heat, then fry each sandwich for about three to four minutes per side. I watch closely and flip once the underside turns a deep golden brown, which also gives the candy inside time to melt completely.
Once they're done, I let the sandwiches sit for a minute so the melted candy doesn't burn little mouths. Then I slice them diagonally, dust them with powdered sugar, and get them on plates while they're still warm and slightly gooey inside.