Choose the ROAST function. Set to 400 degrees for 30-40 minutes. Small artichokes will cook in 30 minutes, larger artichokes will take longer to cook.
Push the START button. The Ninja Foodi Grill will start to preheat.
While the Ninja Foodi Grill is preheating, prepare the artichokes.Rinse the artichokes and cut the stems off of them. Cut all of the stems off except about ¾ of an inch off. Trim the leaves by cutting the top inch off of the artichoke. Cut the artichoke in ½ or ¼ based on the size of the artichoke.Cut a 12-18 inch long piece of foil. Line up the ½ or ¼ artichokes in a row in the middle of the foil. Drizzle with olive oil, top with minced garlic and lemon slices. Wrap the sides of the foil over the artichokes. Then, wrap the top and bottom so that the artichokes are completely covered in foil. If needed, wrap in a second piece of foil to make sure they are completely sealed. Place the artichokes wrapped in foil into the crisping basket.
Once the Ninja Foodi Grill has finished preheating and says ADD FOOD, open the lid and place the crisping basked with the wrapped artichokes into the Ninja Foodi Grill.
About halfway through the full cook time, open the lid and flip the foil packet of artichokes. Close the lid and continue cooking.
When the cooking time is complete, open the lid remove the foil packet of artichokes. Carefully open the packet and place the artichokes onto a plate.