Preheat oven to 325 degrees.
In a warmed skillet, saute onions in the olive oil until soft and tender.
Add garlic and cook for about 1 more minute.
Add remaining sauce ingredients to the pan and bring to a simmer.
Cook for another minute, take off the burner and allow the sauce to cool some, then place in a blender and puree.
Place the ribs in a large roasting pan and season with salt and pepper.
Pour sauce over the ribs and toss around to evenly coat the ribs in sauce.
Cover with foil and bake for 30 minutes.
Increase oven temperature to 400 degrees.
uncover the ribs and continue to cook for another 30 minutes.
Turn the ribs about halfway through.
Transfer to a plate and allow to cool slightly before serving.