1. Cut the cauliflower lengthwise, including the stalk, into 3/4-inch slices. Set aside.
2. In the bowl of a food processor or blender, add the basil, garlic, and lemon juice. Turn on the machine and pulse a few times. Slowly add the olive oil in a constant stream while the food processor or blender is running. Stop to scrape down the sides of the food processor with a rubber spatula. Pulse again until smooth. Season with salt and pepper.
3. Brush both sides of the cauliflower steaks with pesto. Place on a grill over medium heat. Grill for 3 to 4 minutes on each side or until cauliflower is tender but still firm. Serve warm.
Note: I made a vegan pesto for this recipe, but the cauliflower steaks are also great with our Spinach Basil Pesto. You can also use store bought pesto if you wish.