I have grown Yacon (also called the earth apple in the Andes where it originates ) for a few years now and value it as a raw treat in autumn and winter while working in the garden. Its tubers are still valued as a water source in some parts of South America but also more importantly, they are rich in the indigestible sugar – inulin – which is used extensively in the Philippines in the making of sweets . Also a vital sweetening agent for diabetics and without the calories.
Yacon is a perennial plant, easy to grow in soil which tomatoes would do well. I plant it along the edges of my gardens as it tends to grow to a metre or more. It sets small daisy like yellow flowers in autumn after which I begin to scrape the soil away from around the large edible tubers alongside smaller yam like tuber roots ( pups ) which will be re planted for next years crop.
Various uses in the kitchen and I recommend a google or other search for a myriad of recipes. I like it raw in salads or just as it is. Another use is in a stir fry.The leaves too shouldn’t be undervalued as the can be used as a successful substitute for vine and cabbage leaves.