What are the snack businesses suitable for summer business?

I met him at the gate of a scenic spot when I went out to play before. An old woman is holding a simple small refrigerator with some frozen mung bean porridge in it. I think the cost of this small business will be very low at first, and it needs an incubator and mung bean porridge cooked at home. Moreover, mung beans themselves can relieve summer heat, especially when traveling, so many people will buy them.