From Unofficial Stationeers Wiki
Baked potatoes are made by cooking a potato in the microwave.
It takes a very long time to consume and only fills up 80% hunger, so it's better to make fries if possible, which consumes much faster and fills 160% hunger at the additional cost equivalent to 5 soybean (5 ml Soy Oil)
When right button is held, only adequate part is consumed to fill hunger up to 100%.
Percentages of it can be eaten by holding down and relasing the right mouse button.