Leave the skins on the potatoes and cut away any spots or blemishes, then cut into 1½ inch cubes, skin left on. Place into a large bowl as you cut and drizzle on some of the oil to coat, which will stop them from oxidizing (turning brown) in the air. Continue cutting and oiling using up all of the oil.
Sprinkle on the pepper as you toss the oiled potatoes so the pepper gets distributed evenly. Then pour out onto a foil lined sheet pan and place in the oven in a single layer. Roast for 20 minutes, remove from oven and flip the potatoes then roast for 15 minutes more or until tender.
While potatoes are roasting, make the glaze by heating a large skillet or sauté pan over medium heat with the butter and sesame oil. Add garlic and cook for two minutes then remove from heat and stir in the miso, soy, brown sugar and water. Stir to mix then set aside. It won’t look like much but it is just enough to glaze the potatoes.
When the potatoes come out of the oven, return the skillet to high heat and pour in the cooked potatoes, including any oil left on the sheet pan.
Use a rubber spatula or turner and gently toss the potatoes and glaze until they are coated. Cook just long enough to crisp them up a bit then remove from heat and sprinkle on the sesame seeds while tossing with the spatula. The seeds will stick to all wet surfaces. If you wait too long, the potato surface will dry and the sesame seeds won’t stick.
