Combine all ingredients in a medium saucepan.
Heat over medium stirring constantly until the mixture starts to resemble mashed potatoes.
Remove & transfer to a glass bowl.
Cover with a damp towel & allow to cool at room temperature for about 30 minutes.
Once cool, preheat oven to 175 degrees.
Place clay on a sheet of parchment paper & roll out flat. (if it's still sticky you can add a little more cornstarch)
Cut into desired shapes, stamp with any stampers you choose & transfer to parchment lined baking sheet.
Bake 30 minutes - flip over & bake another 30 minutes.
Let stand at room temperature for 24 hours before painting.