Preheat the oven to 350 degrees F. Slice the cauliflower head into 1 1/2-inch to 2-inch slices. Heads up: depending on how big the cauliflower head is you will probably end up with 3-4 "steaks." You can keep or discard the scraps, if you like. I ended up keeping them and putting them in a salad later on that day.
To a 13-inch x 10-inch casserole dish, mix together the chicken broth, olive oil, juice from the lemon, garlic cloves, cumin, red pepper and sea salt. Gently transfer the cauliflower steaks to the casserole dish and place in the oven. Roast the cauliflower for 30-35 minutes.
While the cauliflower is roasting, let's make the gremolata. Add all of the ingredients to a food processor (minus the lemon and salt) and pulse until mixture is coarse. (Alternatively, using a knife, you can mince all of the ingredients separately.) Squeeze in the juice from the lemon; mix and salt to taste. Set aside.
Remove from the cauliflower from the oven and allow to cool slightly for 5-10 minutes. The cauliflower will be fragile so be gentle when handling. Transfer the cauliflower steaks to a bed of paper towels to and dry. Meanwhile, heat a cast iron skillet over medium heat. Add a few tablespoons of olive oil to the hot pan and gently add the steaks, searing them for 1-2 minutes on each side and until golden brown. Drain the steaks on a bed of clean paper towels. Serve immediately with a few teaspoons of gremolata on each.