This is a recipe we found and loved so much it's now a family tradition. It's easy to make and really tasty, whether you leave it in "bark" pieces or use a cookie cutter to make it extra cute. You can also reduce the marshmallows and add the same amount of crispy rice cereal to make them crispy, mmm!
First, measure out 3 cups of marshmallows. Line an 8×11 glass dish or a half-sized cookie sheet with parchment paper. the smaller the dish, the thicker the bark.
Put white chocolate and shortening in a medium sized glass bowl. Add shortening if desired. Melt chocolate in the microwave for 1 minute. Give it a small stir, then return to the microwave in 30 second increments, until chocolate melts completely when you stir it. Stir for 20-30 strokes to make sure it is melted rather than ovrcooking. Chocolate may not look melted but when stirred it is. If overcooked it will "seize" and it's no good- toss it out and start over. It should be done in about 2 minutes, depending on your microwave.
After chocolate is completely melted, add marshmallows and stir to coat. You’ll want to do this kind of quickly but make sure the chocolate coats the marshmallows completely. If you take too long the marshmallows will start melting.
Transfer marshmallow mixture to your prepared pan. Butter a rubber scraper,and use it to make sure marshmallows extend to the edge of the pan. Press down slightly to even it. Shake on sprinkles or decorations if desired.
Freeze for about 20 minutes until set. This will cool the mixture quickly, keeping the marshmallows from melting!
Remove from the freezer and leave on the counter to return to room temperature. Cut into pieces. If you use a cookie cutter, a metal one sprayed with cooking spray prior to cutting works best.