Heat oven to 375 degrees.
Cut sections off of cauliflower head, but removing rounded sections on each side. The cauliflower head should look like a square block. Save excess for a future cauliflower recipe.
Cut 1-1 1/2" thick slices from the square block. Do not despair, some may fall apart. Depending on the size of your cauliflower head, you can cut 3-4 solid "steaks".
Heat cast iron pan with 1 tbsp olive oil over medium heat.
Mince parsley, oregano, mint, garlic, and shallot extra fine. Add all ingredients to a small bowl.
Add 2 tbsp olive oil and white wine vinegar to the herb mixture. Season with salt to taste.
Place cauliflower steaks in heated pan. Cook steaks until golden brown, about 2-3 minutes each side.
Once cauliflower is golden brown, remove from heat and place in the oven. Add 3-5 whole garlic cloves with skins on. Roast the cauliflower for 15-20 minutes until cooked through (al dente).
Once cauliflower is roasted, plate each head and drizzle with Chimichurri sauce.
Remove skins from roasted garlic and assort throughout the plate as well as left over mint and oregano for garnish.