Heat the oven to 400°F and line a rimmed baking sheet with parchment paper.
In a large bowl, combine the turkey, egg, oats, onion, sage, salt and pepper with your hands until just mixed; do not overmix.
Roll the mixture into 24 meatballs, about 1 inch across, and set them 1 inch apart on the prepared sheet.
Bake 18-20 minutes, until no longer pink in the center and an instant-read thermometer reads 165°F.
While the meatballs bake, simmer the cranberry sauce, orange juice and Dijon in a small saucepan over medium-low heat for 4-5 minutes, until glossy and slightly thickened.
Toss the hot meatballs in the glaze, transfer to a serving plate, scatter with parsley and serve warm with toothpicks.