What is the fluffy white stuff?

I haven't made these for a couple years but since we are going to the lake I did.  They are so much more tasty than grocery store marshmallows.   They are very easy to make, the recipe is from the Joy of Cooking cookbook. Very important to dust the pan better yet dust parchment paper with cornstarch or powdered sugar so they don't stick and stick they will.  Let them dry for at least 12 hours 24 is better.  I used my nylon pizza cutter to cut them into squares, I have tried various knives and a couple different scissors, the pizza cutter works the best. Do not put in the safe spot in the oven so curious individuals don't stick their fingers in the goo. I did that then forgot I made marshmallows and turned to oven on and oops what is that heavenly aroma? a whole pan of toasted marshmallows.  

Hoping your 4th of July celebration is sweet! --Ann--