All the baking ingredients to make Crispy Rice Marshmallow Cookies. Simply pour the mason jar mix into a bowl and add egg, slightly melted butter, and vanilla, according to the directions on the label. Combine and bake at 350 degrees for 7-10 minutes. These mixes make a fun hybrid between a rice crispy square and a cookie. Contains: flour, baking soda, salt, golden yellow sugar, rice crispies, and mini-marshmallows. Jars by Jodi creates mason jar cookie and dessert mixes - perfect for party favours, presents, client gifting, or an easy way to make treats at home. Yield per mix: 12-15 cookies (mini size) 24-30 cookies (regular size).