Put a large pot of water on high to boil with the lid on. The size of the pot(s) depends on the number of artichokes you're making. Trim the stocks down leaving about 1 inch.
Use your fingers to gently open the artichoke. The goal isn't to pull it completely apart, it's to create some space between the leaves for the seasoning and oil to get in. You can use the oil as a lubricant to make this process easier if necessary.
If you haven't already oiled the artichoke do that now and season it with the cajun seasoning. Do your best to pull the leaves apart a little so the seasoning and oil make it inside the leaves.
Once the water is boiling put the artichokes in the water. I like to use tongs to hold each one under the water to let it fill up with water so they stay under the water instead of on top of the water. Boil for 45 mins to 1 hour until the stocks are fork-tender. It might look like you just undid all the flavor you just put on the artichoke but trust me, you didn't. It's like pasta or potatoes, all that flavor in the water boils into the artichoke.
Remove each artichoke from the water stock up to allow the water to drain. Place on a cutting board and cut the artichoke in half from top to bottom. Use the tongs as the artichokes will obviously be very hot. Add a bit more oil and cajun seasoning to the cut side of each half.
Place the artichoke halves cut side down on a high heat grill for 10 - 15 mins or until the edges of the leaves are slightly charred. Remove from the grill and allow to cool.
While the artichokes are cooling mix 1/4 cup mayo with 1/2 tsp of cajun seasoning. Mix until well combined. This dip is so good and so easy.