He can't cook mashed potatoes because there's no place to hold them.
To me, the best way to cook sweet potatoes is to treat them as if they were white.
The potatoes will be cooked only partially after 10 minutes.
Five to seven minutes before potatoes are cooked, add the green beans.
When potatoes are cooked, add to bowl and mix well.
The easiest way to cook new potatoes - fun, too.
Five minutes before the potatoes are cooked, add the broccoli to the cooking water.
Cook for about 5 minutes, or until potatoes have started to soften but are not cooked through.
When the potatoes are cooked, add them to the onion mixture.
When the potatoes are cooked, drain and add to the skillet.