In a large bowl, toss the cauliflower and broccoli with the hot sauce, olive oil, and dry dressing mix.
When the vegetables are well coated, spread them out in a single layer on a baking sheet. Freeze for about 45 minutes and then transfer them into a large resealable bag*. Remove the excess air and freeze.
Preheat the oven to 425°. Line a baking sheet with parchment paper.
Place the frozen broccoli and cauliflower in a single layer on top.
Bake for 10 minutes. Flip the vegetables over and place them back in the oven for another 20 minutes.
Serve beside your favourite main dishes or as a potluck side dish.
*Pro-tip: We like to buy the broccoli and cauliflower frozen in resealable bags from the store. That way, after we assemble this dish, we can put the vegetables back into those same bags, reseal, and store them in the freezer. From the outside, it will just look like a bag of frozen broccoli and cauliflower, but it will already be seasoned and ready to cook. You can label it with a permanent marker if you want.