Preheat oven to 425°F. (Depending on the type of your roasting pan, you may need to lightly grease it.)
Cut off and discarding leaves and stem off of the head of cauliflower.
Wash it and pat it dry.
Cut cauliflower into florets. (Smaller florets will cook faster and preferred for better roasting.)
Combine cauliflower florets with oil, salt, pepper, and garlic powder in a mixing bowl. Mix until all cauliflower is evenly seasoned.
Spread seasoned cauliflower in a baking sheet in one even layer and make sure the baking sheet is big enough not to crowd the vegetables.
Bake for 20-25 minutes, until golden brown. (Add a few minutes if you want the cauliflower softer or take away a few minutes if you want it to remain crunchier.)
Notes
To Cook In Air-Fryer: Depending on the size of the air-fryer you have, you can do it in one batch or divide it into two batches. (You don’t want to overcrowd it too much.) Prepare the cauliflower florets per the recipe, up to the step of cooking. Spread the cauliflower florets in the air-fryer and cook it at 390°F for 15 minutes. Make sure to shake/toss the florets every 3 minutes to ensure even cooking.
Reheating: I find it best reheated on stove-top, in a preheated pan. Make sure to preheat the pan all the way, add a little bit of oil, and sauté roasted cauliflower just until it heats through.