Adjust oven rack to the lowest position possible and preheat your oven to 450 degrees. Get out and measure all of your ingredients.
Slice your sweet potatoes to about ¾ of an inch thick.
In a bowl, toss potatoes in oil and about 1 teaspoon of salt. Space potatoes in a single layer on your rimmed baking sheet. Bake until potatoes are tender and starting to brown on the bottom, somewhere between 17 and 22 minutes. Don't forget to rotate your sheet at about the 10 minute mark. That's what I always do.
While your sweet potatoes are baking, grab a small saucepan and combine maple syrup, water, butter, cornstarch, and 1 teaspoon of salt. Bring to a boil over medium high heat and cook, until thickened and reduced to just over 1 cup. You'll be stirring constantly for around 6 or 7 minutes.
Place potatoes brown side up in a 13 by 9 inch baking pan, shingling or layering like shingles on a roof if necessary. Pour syrup mixture over top of potatoes and bake until bubbly around edges, between 8 and 10 minutes.
Transfer dish to wire rack and allow to cool for about 10 minutes.
Season with pepper to taste. Serve and enjoy every bite!