Preheat oven to 400 F. Lightly spray 9-inch pie pan with nonstick cooking spray.

In medium bowl, using box grater, grate sweet potato. Measure out 2 cups. Gently press sweet potato on bottom and up sides of pan, forming crust. Sweet potato will be loose but will hold together once cooked.

Bake 20 minutes, or until crust is cooked. Remove from oven. Let stand to cool. Reduce oven temperature to 350 F.

In medium skillet, heat oil over medium-high heat, swirling to coat bottom. Cook onion 6 minutes, or until almost translucent, stirring frequently. Add turkey bacon. Cook 3-4 minutes, or until onion and bacon begin to brown, stirring frequently. Add spinach, dillweed, salt and pepper. Cook 1-2 minutes, or until water from spinach is released. Remove from heat. Transfer mixture into sweet potato crust.

In medium bowl, whisk egg whites, eggs and milk. Pour over mixture in crust. Sprinkle feta over top.

Bake 35-40 minutes, or until knife inserted into center comes out clean. Transfer to cooling rack. Let cool 10 minutes before cutting into wedges.