Stir the soy sauce into the miso paste, breaking the miso apart as you stir. Stir the sugar into the soy sauce mixture. Add in the peeled garlic cloves and the oil. Heat the mixture in a small pot on the stove over medium heat. Bring just to a simmer. Simmer for 5 minutes. Allow to cool slightly, and carefully pour mixture in a small jar with a tight-fitting lid. Store the jar in the fridge for 2 weeks before using.