Do not overmix the meatball mixture or they will turn dense and rubbery. Add the gochujang glaze only in the last 5 to 7 minutes of cooking to prevent burning. Always line your baking sheet with parchment or cooking spray to protect the caramelized glaze. The peanut sauce can be made ahead and refrigerated for up to 5 days. Adjust the gochujang quantity up or down to control the heat level. For a gluten-free version, substitute tamari for soy sauce and use almond flour instead of panko.