PMom asked me for this recipe, so I figured since I had to type it out anyway, I'd post it here.
6 medium yams (You can use sweet potatoes too, but I prefer yams)
1/2 cup packed brown sugar
3 Tablespooons butter
3 Tablespoons water
1/2 teaspoon salt
Wash yams, but don't peel. Heat salted water (1/2 tsp to one cup water) to boiling (should be enough to cover potatoes, but don't put them in until the water boils). Add potatoes. Cook until tender, about 30 to 35 minutes. Drain, cool slightly, and slip off skins (don't burn fingers

). Slice potatoes into 1/2" slices. You can skip all this and buy the canned ones, but fresh is MUCH better.
Mix brown sugar, butter, water, and salt in pan. Cook over medium heat, stirring CONSTANTLY, until smooth and bubbly. Add sweet pototoes and stir GENTLY until glazed.
You can add marshmallows on top, but I don't. It is plenty sweet already.
Enjoy!
Edited to add. I'll usually double the brown sugar sauce mixture.