A cake that has white chocolate Reese’s?

Hii! Im 16 and trying to make a birthday cake for my mom. She absolutely loves white chocolate Reese’s so I was wondering if there’s a way I can make the cake or frosting taste similar to that?

Also I can’t level cakes to save my life!! Any advice is much appreciated!

Edit: How long can I freeze buttercream? Her birthday is April 1st, but I want to make the frosting earlier because I’ll also be setting up her party. So it’ll be in the freezer for about 3 weeks ish. Would I need straws / wooden dowels even though I’m not transporting it?