Epic Sweet Potatoes

In her book, The Flavour Equation, Nik Sharma breaks down the science of the Ultimate Sweet Potato; both in flavour & texture. We've put a "garlic" spin on her research.
Ingredients:
- Sweet Potatoes - 4
- Unsalted butter - 2 tbsp
- Epic Garlicky Fry Salt - 1 tsp (or to taste)
- Optional Side Dressing -
- Creme Freche (or sour cream) - 1/2 cup
- maple syrup - 1 tbsp
- Lime juice - 1 tbsp
- fish sauce (optional) - 2 tsp
Instructions:
"A combination of steaming and roasting works great for a dish like this for both the texture and the extra set of aroma molecules that comes through. The first step, partial steaming, keeps the moisture inside the sweet potato while cooking, and the second step, uncovered roasting, helps create a robust flavor profile.
“The Flavor Approach: Butter works as the fat of choice here due to its higher smoke point. As the butter melts, it separates into its constituents—fat, water, sugars, and milk solids—which undergo caramelization and the Maillard reaction. The sugars concentrate as the water evaporates during cooking." - from the Flavour Equation
The Epic Garlicky Fry Salt is rich with local garlic with a hit of Korean chili pepper for heat and nutritional for that spot of umami taste, both as a cooking & finishing salt.
METHOD:
1) To prepare the sweet potatoes, heat the oven to 400°F (200°C).
2) Rinse and scrub the sweet potatoes under running tap water. Slice lengthwise and place them in a roasting pan, cut side facing up. Brush or smear with the butter and season with Epic Garlicky Fry salt. Cover the pan with a sheet of aluminum foil and press around the edges to seal snugly. Bake for 20 minutes.
3) After 20 minutes, remove the foil, flip the sweet potatoes, and cook, uncovered, for 20 minutes more, until the sweet potatoes are cooked thoroughly and are tender; a knife inserted into the center of the sweet potato should slide through easily. Remove from the heat and let rest for 5 minutes.
4) To prepare the dressing, in a small bowl, combine the sour cream or crème fraîche, maple syrup, lime juice, fish sauce (optional) and season with Epic Garlicky Fry salt to taste.
5) To serve, top the warm roasted potatoes with a few tablespoons of the maple crème fraîche dressing. Sprinkle with the scallions, peanuts, chile flakes, and lime zest. Serve with the extra dressing on the side.