I couldn't resist posting the recipe for these fabulous treats, adapted from epicurious.com. Browning the butter gives them extra flavor. Take care not to burn the butter as it can happen quickly.
COOKIE RECIPE HELP

INGREDIENTS
8 ounces unsalted butter, plus extra for greasing pan
1/4 teaspoon salt
1 package (10 oz., about 40) JET-PUFFED Marshmallows or 4 cups JET-PUFFED Miniature Marshmallows or 1 jar (7 oz.) marshmallow crème; for best results use fresh, unopened bags  
1 12-ounce box Rice Krispies Brand cereal or Rice Chex Brand Gluten-free Cereal, crushed

INSTRUCTIONS
1. Spray a 13- x 9- x 2-inch pan with cooking spray. Set aside.

2. In a large pot, melt butter over medium-low heat. It will melt, then foam, then turn clear golden and finally start to turn brown and smell nutty. Watch closely and stir often.

3. When butter is evenly browned, stir in salt and then, marshmallows. Melt and cook, stirring often, until mixture turns pale brown, then stir constantly until lightly browned but not dark, 3 to 5 minutes.

4. Turn off heat, add cereal, and mix well, preferably with a silicone spoon or a spatula. Scrape into prepared pan and press down lightly. If necessary, butter hands to press mixture flat. Let cool, and cut into evenly sized squares or bars.

STORAGE

They are best served the same day. Store at room temperature for a few days (2 days is optimal) placed in an airtight container.

To freeze, place in layers separated by wax paper in airtight container. Freeze for up to 6 weeks. Let stand at room temperature for 15 minutes before serving.