Flip the baby back ribs meat side down. Run a sharp knife under the membrane. Take a paper towel to grip the membrane and pull it off the ribs. Set aside.
To prepare the lemongrass stalk, remove the woody outer layers. Thinly slice it with a sharp knife.
In a food processor, add in the sliced lemongrass, garlic cloves, apple cider, kosher salt, black pepper, and 2 tablespoons of the Noble Made Classic Marinade. Pulse until a rough paste forms and everything is well combined.
Rub the rough paste all over the baby back ribs making sure all sides are coated. Marinate for at least 2 hours to overnight.
Instant Pot method: place trivet into the Instant Pot, add ½ cup water, place ribs on top of the trivet. Close lid, seal the valve, and cook at high pressure for 20-25 minutes depending on how tender you want the ribs. Once done, let it naturally release before removing. Remove ribs from the Instant Pot and place on a rimmed baking sheet lined with foil or parchment paper
Oven method: preheat oven to 350F, place ribs on a foil lined rimmed baking sheet and bake for 2-2 ½ hours. Remove from oven.
During the last 10 minutes of the ribs cooking, regardless of which cooking method used, add 1 cup of the Noble Made Classic Marinade and fish sauce into a saucepan.
Bring to a boil, and then lower the heat to bring the sauce to a simmer. Meanwhile, mix the arrowroot flour with the warm water to create a slurry.
Add the slurry to the marinade, mix until well combined, and simmer until sauce thickens. Remove from heat.
Brush the marinade onto the baby back ribs on both sides (a little goes a long way), and then add the baby back ribs into a preheated 450F oven. Roast for about 5-7 minutes to help caramelize the marinade.