This is an excellent start to a really fun crafting game! I don't believe it fits the summer theme, even though i definitely have tasted some smores that feel like they were made out of wood and stone... That being said, I would strongly recommend you add important player feedback like audio (so they know each click is resulting in "work"), and perhaps some type of finished animation or display when i craft a new smore.
You could also require the player to have intermediate steps... for example, picking up a marshmallow requires you go to a camp fire to play a minigame where you roast it. I would say 90% of smore making is about the marshmallow + fire experience, especially when your friends dangerously whip around molten sugar and risk catching us all on fire!