Grilling is one of America's favorite pastimes. My mom used to grill meat in our garage in unfavorable weather, which was probably not the safest practice, but a lot of fun. I still remember sitting on the steps staring at the small little grill she had covered in tin foil, watching her flip pieces of juicy meat over with chopsticks, and smelling the sweet smoke. This chicken recipe is guaranteed to be a hit. It is so ubiquitously delicious--even your Korean food doubter friends with gladly chow this down.
For the marinade and chicken: In a large bowl, whisk together the soy sauce, brown sugar, maple syrup, vinegar, chile paste, ginger, sesame oil, sesame seeds, black pepper, salt, garlic and spring onions. Reserve about 1 cup (235 milliliters) to make the glaze.
Place the chicken thighs in a medium bowl and pour in the remaining marinade, making sure all sides are covered. Cover and place in the fridge for at least 4 hours and better yet, overnight, to let the flavors infuse.
Preheat the oven to 450 degrees F (230 degrees C). Bring the chicken up to room temperature for 30 minutes to 1 hour before grilling.
Wrap the sweet potatoes in a sheet of foil, sealing well. Bake until a small knife goes all the way through the potatoes easily, about 1 hour. Let cool slightly, then peel the skins off and discard. Place the potatoes in a small bowl and mash roughly with a fork. Cover and set aside in a warm place.
In the meantime, bring a grill or griddle pan to medium-high heat. Brush lightly with vegetable oil. Shake the excess marinade off the chicken and place on the grill skin-side down first. Cook until cooked through, flipping once, about 15 minutes. Let rest in a warm place while you cook the corn.
Place the corn on the grill and cook, turning often, 9 to 10 minutes. Cut each piece down the center lengthwise.
To serve, transfer the chicken to a serving plate or platter. Brush the chicken very lightly with the glaze, or serve it on the side as a dipping sauce. Garnish the chicken with the chile threads. Finish the sweet potatoes off with a sprinkle of black sesame seeds. Serve the corn with the doenjang mayo on the side or brush it on to the hot corn, letting it melt into the crevices.