Rocky road chocolate bark - great, easy holiday gift

Each year I make a homemade chocolate bark as gifts for my kids teachers, hostess gifts, etc. I love this recipe because it's 1) fast; 2) easy; 3) kid-friendly; and 4) absolutely scrumptious! The secret -- using the microwave instead of a double boiler to melt the chocolate. I timed myself this year and it took about 25 minutes to make a double batch!

Ingredients:
- About 2 pounds of milk chocolate. I use 3 11.5 oz bags of Guittard milk chocolate chips. I've also used Ghiradelli chips as well, but can't taste the difference. You can also use regular chocolate blocks.
- 1 tablespoon solid vegetable shortening
- 3 cups mini-marshmellows
- 3 cups chopped walnuts

Directions:
1. Prepare a large cookie sheet (12 x 17.5 inches) by lining it with parchment paper, lightly sprayed with an oil spray. In a pinch, you can also use plastic wrap.
2. Place the chocolate and shortening in a large glass bowl. Heat on high for one minute and then stir with a spatula. Repeat heating for one minute and stirring until the chocolate is completely melted.
3. Stir in 2 cups of the marshmellows and 2 cups of the walnuts.
4. Pour the mixture on to cookie sheet and spread out to about 1/2 inch thick (or thinner if you prefer).
5. Sprinkle another cup of marshmellows and cup of walnuts on top of the chocolate and then gentle press it into chocolate. This is a great step for the kids as they LOVE to like their hands clean!
6. Cool at room temperature until completely firm, about 4-6 hours or overnight. Cut or break the bark into pieces. Store bark in an airtight container for up to 2 weeks.

For presentation, I get cellophane gift bags and fill them with the bark, tying off the top with some curling ribbon.