3 cups Semisweet Chocolate Chips, Or milk chocolate chips, divided
Line a loaf pan with wax paper. If necessary, cut slits in the corners of the wax paper so it fits well.
Place 2 cups of the chocolate chips in a microwave-safe bowl. Microwave for 90 seconds at 70 percent power. Stir and continue to microwave at 15-second intervals until the chips are almost melted. Stir the chips using residual heat to completely melt the chips. Scrape the chocolate into a disposable decorating bag, twist the top, close with a rubber band and snip 1-inch from the tip.
Pipe back and forth in the loaf pan to cover the bottom with a thin layer of chocolate.
Place a layer of wafer cookies on top of the chocolate. You should fit 8 to 9 cookies in a row.
Pipe another layer of chocolate to completely cover the top of the wafer cookies, being sure to pipe around the edges. Place a second layer of wafer cookies on top of the chocolate.
If necessary, melt the remaining 1 cup of chocolate chips and pour into the decorating bag. Pipe chocolate to cover the top of the wafer cookies.
Let set until the chocolate is firm to the touch, about 2 hours at room temperature or 1 hour in the refrigerator.
Slice 3/4-inch pieces with a sharp knife and serve.