We do prefer to make our own Cajun spice mix (the ingredients are given below) but it is quite alright to use store-bought. Whichever you decide to use, make sure that you give the ribs a few hours to soak up the spice mix before sticking it in the oven.
Make the Cajun spice mix by whisking together all the ingredients (see notes after the recipe).
Wipe the rack of ribs with paper towels.
Whisk together the Cajun spice mix, salt, tarragon, rosemary and lemon and pepper seasoning. Rub all over the ribs.
Wrap the ribs with cling film and allow to marinate for at least two hours in the fridge (or overnight for best results).
Preheat the oven to 300F.
Take the ribs out of the fridge. Discard the wrapping.
Take a large piece of aluminum foil and place it on a baking tray. Lay the ribs on the foil. Take another large piece of foil and lay over the ribs. Gather together the sides of the top and bottom sheets of foil and crimp to seal in the ribs. Make sure that there are air pockets inside the package. You want steam to build up inside to help keep the meat moist.
Cook the ribs in a 300F oven for two hours.
Meanwhile, whisk together in the ingredients for the glaze.
Take the ribs out of the oven.
Turn up the temperature of the oven to 400F.
Carefully unwrap the ribs (be careful of the steam that will escape!) and discard the top layer of foil.
Brush the glaze all over the ribs.
Put the ribs back into the oven and leave for 10 minutes or until the glaze turns into a light sticky crust.
Take the ribs out of the oven. Rest for a few minutes. Cut between the bones. Plate up, sprinkle with sliced chilies and parsley, and serve.