Mom's Yams & Apples

Boil 4-5 peeled yams for 20 minutes. Cool, then slice. Peel 4-5 apples and slice. In a buttered casserole dish alternate starting with apples and ending with yams (or just mix together).
Meanwhile, make sauce...

Sauce:
2 c. water
3-4 Tbs. cornstarch
1 c. sugar
1 stick butter (8 Tbs)
1 tsp. salt

 Cook sauce over medium heat until thick and clear.
Pour over yams and apples and bake at 350 degrees for 1 to 1 1/2 hours.