Before you do anything with your ribs, remove silver skin from the back of the rib racks. Unlike other connective tissue — like collagen, which slowly dissolves into gelatin during cooking — silver skin does not break down. When left attached to the meat, it cooks up tough and chewy. You don't want that. I find that the easiest way to remove silver skin is to pry it up at the bone with the tip of a handle of a small fork or spoon, then I run my fingers between the skin and the rack. You want to start somewhere in the middle of the rack. If it breaks just grab the side and slowly pull away to one of the sides. You can use a paper towel to get a good grip if it's too slippery.
Cut the racks into two-rib sections. This is not the typical procedure when cooking baby back ribs, but I prefer doing that. The simple reason is that I don't have to mess with slicing hot rib racks afterward. It's not easy and the meat tends to tear when it's fall-off-the-bone tender. Pre-cut ribs look neat and presentable. Try this, you will thank me later.
Apply dry rub and garlic. I always apply the dry rub to the meaty side of the rib rack. There is no meat on the other side so applying seasonings there is pointless. Some folks like to wet the ribs with a couple of teaspoons of vegetable oil or yellow mustard to make the spices stick better. I used to do that but not anymore. I find that my dry rub sticks to the meat just as well without oil or mustard. That said, either approach is fine so pick whichever you like best. Place the ribs on a baking sheet or dish and cover with foil. Make sure that whatever you will be baking the ribs in has at least 1 inch-high walls as the ribs will release some water during baking. The ribs are now ready to be baked. If time permits, let them sit at room temperature for about an hour. This will allow the seasoning to penetrate the meat and the meat will come up to room temperature and won't sweat in the hot oven once you put it in.
For best results, I always recommend marinating ribs overnight in a fridge. The rub will have ample time to penetrate the meat and the flavors will meld together in a beautiful bouquet. The aroma of fresh garlic is mind-blowing. I love garlic flavor in my ribs. I find that the usual granulated garlic tends to remain grainy and you can feel that grainy texture when eating ribs. Fresh garlic is much better in that you don't feel it in your mouth. Fresh garlic will give a very strong pungent smell initially but it will mellow down completely by the time the ribs are fully cooked.
After marination, let the ribs sit at room temperature for about an hour before baking while the oven is preheating. If in a rush, you can stick them in the oven once it's preheated without letting them sit out.
In this step, is the first, and the easiest part of my 3-300-30 baking method for baby back ribs. All you have to do is stick the ribs in the oven, cover with foil, and bake for exactly 3 hours at 300F. It's as simple as that.
After 3 hours of baking, carefully remove the ribs from the oven. There will be quite a bit of hot juices in the pan so make sure you don't spill them. Pour most of the juices out, leaving about a cup in the baking pan.
Apply BBQ sauce quite liberally over the ribs and spread it evenly with a baster over tops and sides. There is really no need to paint the bones on the other side with BBQ sauce. I normally use about a cup and a half of BBQ sauce per two racks of baby backs. If the sauce is thick I may use more since it won't be running off easily. If the sauce is fairly liquid and runny I may only use a cup. So keep that in mind. There is no right or wrong here. Use your judgment and make them how you like them.
Return the ribs back in the oven, uncovered, for 30 minutes. This is the final step of my 3-300-30 method. The temperature will stay the same at 300F. I find that 30 minutes at 300F is enough to let the sauce set and stick to the ribs very nicely. If you see that it didn't, give them another 5-10 minutes. If you like the sauce a little more runny, pull them out of the oven after 15-20 minutes.
Now, remove your finished ribs from the oven and enjoy with your favorite side dish.