Roasted Sweet Potatoes

 From Serious Eats

 Ingredients

• 5 pounds sweet potatoes, peeled and cut into 1/2-inch disks or 1/2-inch chunks
• 1/4 cup olive oil
• Kosher salt and freshly ground black pepper

Directions

1. Bring 3 quarts water to a boil in a large saucepan over high heat. Remove from heat and add 1 quart room temperature (70°F) water to pot. 
2. Immediately add potatoes to pot and cover. Place in warm spot in kitchen for at least 1 hour, and up to 3.
3. Meanwhile, adjust oven racks to upper middle and lower middle positions and preheat oven to 400°F.
4. Drain sweet potatoes and transfer to large bowl. 
5. Toss with olive oil, and season to taste with salt and pepper. 
6. Spread sweet potatoes on two rimmed baking sheets and roast until bottom side is browned, about 30 minutes. 
7. Carefully flip potatoes with thin offset spatula and roast until second side is browned and potatoes are tender, about 20 minutes longer. Serve immediately.
   

As long as you're water's above 135 and below 170°F, it'll have a positive effect on their flavor.  "Moist sweet potato varieties sweeten during cooking thanks to the action of an enzyme that attacks starch and breaks it down. The enzyme starts to make maltose when the tightly packed starch granules absorb moisture and expand, beginning around 135°F, and it stops when the rising heat denatures it, at around 170°F."

Comments
I make this every year at thanksgiving, plain ol'yams are the best!