Preheat your oven to 400 degrees F. Scrub the potatoes under cold water, and then pat them dry with a paper towel as best you can.
Place the potatoes on a baking sheet. Use a fork to pierce the potatoes all over (just to pierce the skin so steam can escape). Brush the outsides of the sweet potatoes with olive oil.
Bake for 1 hour to 1 hour and 15 minutes. The sweet potatoes are done when a knife or fork slides all the way through with no resistance. (The potatoes will darken in color and some of the sugars may run out, this is normal.) Remove the baking sheet from the oven and let the potatoes cool for 10 minutes.
Cinnamon Butter
While the potatoes cool, make the butter. In a medium mixing bowl, beat the butter, brown sugar, cinnamon, vanilla, and salt together with a hand mixer for 2 minutes until smooth, light, and fluffy.
To serve: Slice the potatoes down the center to open the top. Fluff the insides with a fork and top with some of the whipped cinnamon butter. Serve warm.
Notes
Nutritional information is for 1 sweet potato with 2 tablespoons of cinnamon butter.
The butter recipe makes 1 cup of cinnamon butter. Store any leftovers in the fridge in an airtight container.
You can use your hands to rub the olive oil all over the potatoes instead of a pastry brush if you don't have one on hand.