Cut dark patches off sweet potatoes. Do not peel.
Thoroughly rinse sweet potatoes. Pat dry with paper towel or clean dish towel.
Slice in 1/2-inch-thick-rounds. Place in large pot. Cover with water.
Simmer over medium heat until fork tender (firm, not mushy). About 20 to 45 minutes depending upon size.
While sweet potatoes are boiling, preheat oven to 400 degrees and prepare glaze.
In medium saucepan, add unsweetened pineapple juice, 1-1/2 tablespoons fresh lemon juice, dark brown sugar, and salt. Whisk constantly until sugar is dissolved and mixture is bubbly (3 to 4 minutes).
Remove from heat immediately after bubbles form.
Add nutmeg, pure vanilla extract. Stir until well combined. Taste a cooled sample. If desired, add another tablespoon of dark brown sugar and remaining fresh lemon juice. Set aside.
Drain sweet potatoes.
In a 9x13 (or larger baking dish), carefully arrange sweet potatoes neatly in a single layer.
Pour glaze evenly over the top. Cover with foil. Bake 20 minutes.
Remove from oven. Baste sweet potatoes with glaze.
Return to oven (without foil). Continue baking until sweet potatoes are tender (30 to 45 minutes). Baking time depends on thickness.
Serve hot!