01 -
Melt the butter, sugar, and ice cream together in a big heavy pot. Set to medium heat and wait for it to bubble.
02 -
Lower the heat a bit and keep stirring while it simmers for 7-10 minutes. Watch the thermometer hit 234°F.
03 -
Take the pot off the heat, toss in both types of chips, and stir until they blend together smoothly.
04 -
Stir in the marshmallow fluff until everything’s well mixed.
05 -
Pour the mixture into an 8x8 pan, sprinkle on any decorations, and let it cool completely on the counter.
06 -
Pop it out of the pan once cool and cut it into about 24 squares.