Place the olive oil in a small microwave-safe bowl or measuring cup. Cut the rosemary in half or thirds to that it will be submerged in the oil.
Place in the microwave and cook on high power for 1 minute. Swirl the oil in the cup then return to the microwave and cook for 1 more minute. Set the oil aside to steep with the rosemary while you’re steaming the cauliflower.
Place several thicknesses of paper toweling on a dinner plate. Set aside.
Trim the stem and any leaves from the bottom of the cauliflower.
Place the rosemary and broth in a large Dutch oven or pot that has a tight-fitting lid. Add the cauliflower and bring the broth to a boil.
Cover the pot and reduce the heat to medium-low. Allow the cauliflower to steam for 18-20 minutes or until the florets are softened when you insert a small sharp knife and no longer flat white in color.
Using a large spatula or 2 large spoons to carefully (it will be hot) remove the cauliflower from the pot over to the prepared plate. Allow the cauliflower to cool and drain for at least 10 minutes.
At this point, you can cool the cauliflower to room temperature and refrigerate it. About an hour before you’re planning to roast it, remove the cauliflower from the refrigerator to bring it up to room temperature, then proceed to the roasting.
Transfer the cauliflower to the prepared pan with the stem side up. Remove the rosemary from the oil and discard (it’s fine if a few rosemary leaves remain in the oil. Brush the underneath side of the cauliflower with some of the rosemary oil and sprinkle generously with kosher salt. Carefully turn the cauliflower over so the stem side is now down. Use the remaining oil to brush the top and sides then sprinkle with kosher salt.
Roast for 30-35 minutes until medium golden brown.
Remove from the oven and brush with the melted butter. Return to the oven and roast for another 5-8 minutes until beautifully golden brown.
You can serve it immediately but the cauliflower will remain hot and steaming for 15-20 minutes. Sprinkle with finely chopped fresh rosemary and freshly ground black pepper (if desired) just before serving.
See Café Tips above in the post for more detailed instructions and tips to ensure success.
If you prefer to use Metric measurements there is a button in each of our recipes, right above the word “Instructions”. Just click that button to toggle to grams, milliliters, etc. If you ever come across one of our recipes that doesn't have the Metric conversion (some of the older recipes may not), feel free to leave a comment and I will add it.