Preheat the oven to 450 degrees. Prepare a baking sheet with parchment paper.
Cut the cauliflower into steaks: turn cauliflower stem-side up. Using the stem to hold the steaks together, cut into 3 steaks, giving you flat surfaces on each steak. Keep the fallen florets to roast.
Lay the cauliflower steaks on the baking sheet and parchment paper.
Combine the oil, garlic salt, red pepper flakes, and honey in a small bowl. (I like to shake in a small mason jar)
Brush the oil & honey mixture onto the cauliflower. Coat the flowers well!
Roast the cauliflower in the hot oven for 30 minutes total, flipping half way at 15 minutes.
When there is 10 minutes left on the cauliflower, toss the walnuts onto the pan to roast.
Remove and serve with parsley and the optional bed of mashed sweet potatoes!