Prepare a loaf pan by spraying lightly with cooking oil and lining with parchment paper so the paper sticks to the pan. Then lightly spray the parchment paper to prepare for the treats.
Melt 1½ Tbsp butter in a medium pot. Over medium heat, melt the butter.
Remove from the heat and add marshmallows. Stir consistently until marshmallows begin melting. Once marshmallows have started to dissolve, add pot back over low heat and continue stirring until fully melted.
Add the 2 Tbsp instant coffee and give a quick stir to mix.
Add the 1½ cup chocolate Rice Krispie cereal to the pan and stir so everything is coated.
Don’t use your hands, the marshmallow may be hot! Using another piece of parchment paper, or the flat bottom of a glass, press lightly into the corners and flatten the treats. You can also give a light dusting of cooking spray to your surface to help keep it from sticking.