The key to great success in this venture is the truffle. Even better is the Perigord black truffle. If you can figure out how to set up a successful truffle farm in Kenya, using what you already know about growing buttons, that would bring a great return on investment.
There are companies such as Truffle Tree that sell trees that have truffles already growing in them, but they are expensive considering how many you would need for a farm. Maybe you can get one or two, then do research to figure out how to replicate the process locally.
If you can figure out how to "infect" oak or blue gum trees with the truffles, you could be sitting on a "black gold" mine. The demand for your product would be international and unending, as fresh truffles are always loved, but are always in short supply.
Best,
Hill