Preheat George Foreman grill by plugging it in, or setting it to MAX, 400°F or setting 4.
In bowl of a food processor, add all pesto ingredients except olive oil.
Process on low until thick paste starts to form.
With food processor still running, slowly pour olive oil through feed chute until kale has broken up into small pieces. Set aside. (Note: This will be chunkier pesto, and not as smooth as traditional basil pesto. It will also taste quite salty. The salt flavor will even out once on burger.)
In a small bowl, stir together olive oil from “burger” ingredients, dried basil, salt and pepper.
Place mushrooms on a cutting board and brush olive oil mixture over tops and bottoms of mushrooms.
Place mushrooms and halloumi cheese on preheated grill and close lid.
Grill mushrooms for 6 minutes, and cheese for 4 minutes.
Note: If grilling on Indoor/Outdoor grill, grill each for 4 minutes, flip and continue to cook for 2 additional minutes.
To assemble, spread pesto on the bottom of 6 toasted buns. Top with grilled mushroom and grilled halloumi cheese. Place remaining bun on top and eat immediately.