- 1 cup walnuts
- 2 sticks (8 ounces) unsalted butter, melted
- 3 1/2 cups graham cracker crumbs (from one 14.4-ounce box)
- 4 cups semisweet chocolate chips (1 pound 5 ounces)
- One 11-ounce bag butterscotch chips (1 1/4 cups)
- 3/4 cup white-chocolate chips
- One 14-ounce bag sweetened shredded coconut
- One 14-ounce can sweetened condensed milk (1 1/2 cups)
- Preheat the oven to 350°. Spread the walnuts in a pie plate and toast until golden and fragrant, about 8 minutes. Let cool then coarsely chop.
- In a large bowl, mix the melted butter with the graham cracker crumbs until evenly moistened. Press the crumbs onto the bottom of a 15-by-17-inch baking pan. Scatter the semisweet chocolate chips on top, followed by the butterscotch chips, white chocolate chips, toasted walnuts and coconut. Scrape the condensed milk into a microwave-safe container and heat it at high power for 30 seconds, until just fluid. Drizzle the milk evenly over the coconut.
- Bake the bars in the center of the oven for about 30 minutes, until the coconut is toasted; rotate the pan once for even cooking. Transfer the pan to a rack and let the bars cool completely, at least 4 hours. Cut the bars lengthwise into 6 strips and crosswise into 6 strips to make 36 bars.
The bars can be kept in an airtight container at room temperature for up to 5 days, refrigerated for up to 1 week or frozen for up to 1 month.