Preheat your oven to 425F and line a baking tray with foil.
Chop all your broccoli / cauliflower into bite size pieces and throw them in a bowl with your oil and seasonings. Having different sizes is actually good as the smaller pieces will crisp up the awesome-est. Technical term. Stir to evenly coat in oil / spice mixture.
Spread your seasoned veggie out on your baking tray in as even a layer as you can. Whack in the oven for 10 minutes.
Turn the heat up to 450F, flip your veggie pieces over and roast for another 5-ish minutes until edges begin to crisp up. Go for longer if you want moar crispiness, but watch carefully as the risk of blackening instead of crisping increases exponentially 😉