Preheat oven to 400°F and line a rimmed baking sheet with parchment paper.
To make the rice: In a small pot or saucepan, combine 1 1/2 cups rice, 2 cups water, and 1/2 teaspoon kosher salt. Bring to a boil, then reduce to a simmer over low heat and cover for 15 to 18 minutes, or until all water is absorbed. Throw 2 tablespoons butter, and 1 tablespoon sesame oil right on top, and recover for 10 additional minutes to let the butter melt and let the rice continue steaming. Uncover and stir in the melted butter and 2 thinly sliced scallions.
To make the meatballs: In a large bowl, combine 1 pound ground beef, 1/2 cup panko, 1 large egg, 1 teaspoon kosher salt, 1/4 teaspoon garlic powder, and 1/4 teaspoon ground ginger. Roll 15 to 20 meatballs and place on the parchment-lined baking sheet. Bake for 15 minutes, until browned and firm.
Meanwhile, make the Sweet Chili Sauce. Combine 1/3 cup rice vinegar, 1/3 cup white sugar, and 1 tablespoon sambal in a small pot over medium-high heat. Stir until the sugar dissolves. In a small bowl, stir together 2 teaspoons cornstarch and 1 tablespoon water until no lumps remain. Stir it (this is called a cornstarch “slurry” and it helps prevent the cornstarch from clumping up in whatever you stir it into!) into the pot and continue cooking until the sauce goes from cloudy looking, to clear looking. When it is clear and has thickened up, remove it from the heat.
When the meatballs come out of the oven, brush them with the glaze. Don’t have a brush? Just dunk the meatballs directly into the pot of sauce!
Build rice bowls by starting with a base of rice, then piling meatballs, crunchy raw veggies, fresh herbs, and sesame seeds right on top.