Preheat oven to 350 degrees F. Bring a large pot (or 2 small pots) of salted water to a boil. Add sweet potatoes and cook until tender; yet firm, about 20-30 minutes. Drain, let cool.
Peel and dice the potatoes. Place into a large, shallow roasting pan. Mix pineapple, brown sugar, cinnamon and eggs together. Pour into roasting pan and gently stir in with sweet potatoes.
Bake in oven for approx. 30 minutes or until center is hot. While casserole is baking, mix melted butter with pecans. When casserole is done, spread pecan mixture over it, and broil for 5-10 minutes or until nuts are golden brown.