160 vanilla wafer cookies (about 4 1/2 packages)
12 cups white chocolate candy melts, divided
3/4 cup matcha powder
Line 2 bread pans with plastic wrap, double layered. Leave plenty hanging over the sides.
Fill the bottom of each pan with a single layer of wafer cookies. Cut some of the cookies to fit any open spaces. The cookies should completely cover the bottom of the pan with no gaps.
Microwave a few cups of the candy melts at a time until it reaches a smooth consistency. Decrease power at 30-second intervals, stirring between each time.
Stir in 1 tablespoon of matcha powder for each cup of melted candy melts.
Pour about 1/2 to 2/3 cup of matcha chocolate over each layer of cookies, spreading it until the cookies are fully covered. Be sure to add your next layer of cookies before the chocolate hardens.
Continue layering until you've reached the top of the pan. Your final layer will be chocolate. Make this final layer as smooth as possible. You should have at least 4 cups of candy melts remaining.
Allow about 10 minutes for the candy melts to harden. Then, use the plastic wrap to help slide the Kit Kats out of their pans. Place them on a silicone mat, cookie side up.
Melt half of your remaining candy melts and mix it with half of your remaining matcha. Cover one Kit Kat bar as smoothly as possible, making sure to cover the sides. Melt and combine your remaining ingredients and repeat this process for the second Kit Kat bar.
Once both have hardened, cut off any excess chocolate that has pooled around the edges of the Kit Kat bars. Then, position your Kit Kats closely together on the silicone mat. Remelt any matcha chocolate you have, then pour it into the gap between the two Kit Kat pieces. You just want a little at the bottom to connect the two pieces.
Once the chocolate has cooled again, cut off any excess.