Preheat the oven to 160°C. Peel the leaves off the cauliflower and cut the stem, leaving 1 inch or enough for the florets to stay intact. This will leave the base flat and stable on the cutting board and make it easier to cut into the cauliflower evenly. Wet your chef’s knife liberally before cutting the steaks to make the knife slick and nonstick when making contact with the vegetable. Cut 1 inch off the left and right edges of the cauliflower leaving about 5 cm of the center intact. Then slice the remaining portion in ½, resulting in two 2,5 cm steaks from each head of cauliflower. The more even the steaks, the more evenly they will cook.

Drizzle a sheet tray or glass baking pan with 100 grams (or 8 tablespoons) of olive oil. Sprinkle 2 tablespoons harissa powder and 2 pinches of Maldon salt over the oil. Rub 1 side of the steaks in the olive oil/harissa mix and pour 1 ounce of olive oil and the remaining harissa powder over the other sides. Finish with another 2 pinches of Maldon salt. Heat 2 large cast-iron skillets over medium-high heat with 1 tablespoon olive oil in each. Once the pans are smoking, place the steaks in the hot pan and let brown on 1 side for 90 seconds or until the edges begin to char. Turn the steaks over gently, add 2 tablespoons of butter to each pan, melt,and brown to give the steaks a nutty flavor. Baste the steaks with the browned butter. When the butter is frothy, split the vegetable stock into the pans and let it come to a boil. Remove from the stovetop and place side by side on the middle rack of the oven. Roast for 8 to 10 minutes. Use a paring knife to test the doneness of the cauliflower. If you feel resistance, continue cooking; if it pushes into the flesh easily, it is finished cooking. Transfer to a platter to rest.

Mix the olives, olive oil, orange juice, orange zest, lemon juice, lemon zest, and parsley in a medium bowl. Season to taste with salt and pepper.

Heat a large sauté pan over medium-high heat with 2 tablespoons olive oil. Cut the porcinis in 5 mm slices lengthwise and move to the side of the cutting board. Cut the shallots in half lengthwise, then turn them onto the cut side for stability to thinly slice.

Add the porcinis to the pan and cook for 3 to 5 minutes. Season with salt and pepper. Add the shallots and garlic to the pan and continue to cook, stirring occasionally for 5 minutes, or until the shallots and garlic are translucent. Zest lemon into the pan and add the olive pistou. Stir together. Lower the heat to medium-low. Chiffonade the mint and sprinkle over the mushrooms. Add the capers and stir in to incorporate. Turn off heat and season to taste with more salt and pepper if needed.

Plate 2 steaks with the cores facing each other. Spoon the olive pistou/mushroom mixture over the steaks. Finish with a drizzle of olive oil, lemon zest, and lemon juice and tuck the garlic or chive blossoms into the mixture atop the steaks. Plate cauliflower steaks individually if serving as a main.