Preheat the oven to 150°C (302°F) and place the short beef ribs in a large baking pan.
Mix the soy sauce, maple syrup (or honey), and red wine. Pour this mixture evenly over the ribs, scatter the onion slices on top, and cover the pan with foil.
Bake for 1 hour.
Remove the pan from the oven and carefully pour off the cooking liquid into a bowl.
Pour half of the reserved cooking liquid back over the ribs, cover the pan with foil, and bake for 45 minutes.
Remove the cover, add the remaining cooking liquid to the pan, and bake uncovered for 30 minutes until the ribs are tender.