For the Bourbon BBQ Sauce:
(Note, I usually start my sauce after I get my ribs in the slow cooker)
Heat oil in a large pot over medium-low heat. Add the chopped red onion and sauté for 3-4 minutes. Add green onions, sauté for an additional 3-4 minutes. Add garlic and sauté for 2 more minutes.
Mix in all remaining ingredients, adding in the bourbon last. Simmer for about an hour, stirring occasionally. Cover and refrigerate (or freeze) until you are ready to use.
For the Spice Rub:
Wash and dry your rib racks. Remove the silver skin (white membrane) along the bone side of ribs. If it really gives you trouble coming off, you can take a shortcut and just score the membrane between each rib bone.
Cut each rack in half so that they can fit inside your slow cooker. Brush fronts and backs of the rib racks with 2 Tbs of Liquid Smoke (I like Hickory).
Whisk together the dry spice rub ingredients and rub the mixture evenly over all sides of the rib racks. If you are not ready to cook yet, you can cover and refrigerate the ribs for up to 24 hours in advance. They will only get more flavorful that way.
Making Ahead? You can freeze the trimmed and spice rubbed ribs to make for a future date. Wrap them tightly, first with foil, and then again with plastic wrap. Then place the racks in a zip-close plastic freezer bag with the air squeezed out. You can store the racks in the freezer for up to three months. Defrost in the refrigerator and then follow the directions below.
When you are ready to cook the ribs, add 2 Tbs water and 1 Tbs liquid smoke to the bottom of the slow cooker. Stack the rack halves, bone side down, into the slow cooker, with the thickest racks on the bottom and the thinner racks on the top. Cover and cook and on low for 8 hours.
After the ribs come out of the slow cooker, generously brush the racks all over with the Bourbon BBQ Sauce. Arrange on a foil-lined baking sheet that has been oiled with olive oil.
If you are bringing the ribs to a party, you can cover and refrigerate the ribs at this point and bring them (along with the sauce) to the party in a cooler. If the party is close by, just get in the car and go with them. These make a great appetizer!
Heat remaining sauce (not from the bowl used to brush the meat), on the stovetop while performing the next steps.
You can finish the ribs off in the oven on a foil-lined baking sheet. Broil for 3 minutes bone-side-up, and then flip the racks to meat-side-up, brush on more sauce and broil for 3 more minutes. Keep an eye on them; they can go from saucy to burned in a moment.
Alternately, you can finish the ribs off on the grill. Season and preheat a grill to medium. Grill ribs until they are brown and crisp on the edges, brushing with more sauce as needed and turning occasionally, about 10 minutes.
Serve with warmed BBQ sauce for dipping.