Preheat the oven to 425°F and arrange the oven rack to the top position. Gently grease a large baking sheet with olive oil or line with parchment paper.

Place the sweet potatoes and brussels sprouts on one half of the sheet pan. Drizzle with 1 Tablespoon of sesame oil and sprinkle with salt to taste. Toss to coat and arrange them in a single layer with the brussels sprouts cut side down. Roast in the preheated oven for 15 minutes.

While they’re roasting, make the meatballs. Add the breadcrumbs to a large bowl and pour the milk on top. Let it sit for 5 minutes. Chop the scallions and garlic, separating the scallion whites from the greens.

To the breadcrumb mixture, add the beef, scallion whites, ginger, garlic, salt, and Gochujang. Use clean hands to mix until well combined. Use a medium cookie scoop to form the meatballs into 1 1/2-inch meatballs (20-22 meatballs).

Remove the veggies from the oven and place the meatballs in a single layer on the other side of the sheet pan. Drizzle with the remaining sesame oil.

Bake for 14-16 minutes, or until the internal temperature reaches 165°F and the sweet potatoes are tender and the brussels sprouts are golden and crispy.

While they're baking, make the Korean BBQ sauce. Combine all ingredients except the cornstarch in a medium saucepan and bring to a boil over medium-high heat.

Combine the cornstarch and water in a small bowl until dissolved and whisk it into the BBQ sauce. Continue to stir and boil for 1-2 minutes, until thickened. Remove from heat and separate 1/3 cup to a separate bowl for drizzling.

Carefully remove the baked meatballs from the pan and add them to the saucepan with the BBQ sauce, tossing to coat. Place them back on the baking pan. Turn the oven to broil and broil the meatballs and veggies for 2-3 minutes, until the BBQ sauce bubbles and the potatoes get slightly crispy.

Serve with the remaining BBQ sauce and sprinkle with green onions and sesame seeds.