LOL, Andy, those are what we call Ube
. Purple yam, and NO you are not supposed to fry them outright. ROFLMAO! They aren't the same as normal yams.
You boil it (you can add sugar during, or after) then mash it until it has the consistency of thick paste. Then add condensed milk, or whatever you fancy. It has it's own unique taste and smell that reminds filipinos of home. It's also my mom's favorite flavoring for anything from ice cream to cakes. But you never ever treat it like it's a potato. LOL! In it's natural state it has this thick sticky mucus-like juice that's very unappetizing, and yep it's bitter when unseasoned.
We grew up with those growing in our backyard in addition to Camote
(Sweet Potatoes), so I'm quite sick of both of them. Dad used to fry them into chips and coat them with caramel. One of his favorite snacks in addition to fried plantains. They taste alright, but the sweetness gets to you sooner or later. I prefer potato fries really.
Be warned that both yam and sweet potatoes are almost wholly carbohydrates with very little protein. And with fried sweet potato chips, the fat content is almost half of the carbohydrate content.
BTW, pinny why are yams bad for you?
Also a little known fact: The young leaves of sweet potatoes (The ones which are still folded up and a bit purplish) can be eaten in a salad dipped in vinegar, onions, and tomatoes. My eldest sister loves them.