- On the stove in a small saucepan, bring the other 1/2 cup of water, sugar, corn syrup, and cream of tartar to a boil. Use a candy thermometer and boil until it reaches 240 degrees (about 8 minutes once it starts to boil).
- Meanwhile, melt butter and set aside to cool.
- Remove syrup from stovetop once it reaches 240 degrees.
- Start the mixer on medium speed and slowly pour the hot syrup into the gelatin, which should have swelled by now.
- Once it is all poured in, increase speed to medium high to high. Beat mixture until it becomes white and fluffy, and has about tripled it's size (approximately 5 mintues).
- Pour in salt, vanilla, and butter flavoring (if using) and mix until blended in. Then pour in melted butter; the size of the mixture will decrease a little. Mix until blended.
- Transfer into another bowl (if you want) and then stir in the cereal until it is well-coated. Add more or less, depending on how gooey you like your rice krispie treats!
- Transfer coated cereal to baking dish and stick in the refrigerator for about 15 minutes to set.
- Cut into bars and eat, or store in an airtight container.
**If you don't have corn syrup, you may substitute with sugar. So, it would be 2 cups of sugar and no corn syrup.**









