Preheat two half sheet pans in 400F oven for 30 mins.
Separately break down the cauliflower and broccoli into small florets than can fit on a small spoon.
Coat the cauliflower florets in a bowl with olive oil
Add 2-4 tsp of salt to taste.
Place cauliflower in bowl and reserve.
Break down broccoli into small florets
coat with olive oil and season with 2-4 tsp of salt to taste, reserve in separate bowl
Remove sheet pans from oven, evenly distribute cauliflower on one, and broccoli on the other.
Roast in 400F oven for 15 mins, then remove sheet pans and add in your minced garlic to the cauliflower and broccoli and toss on sheet pans to ensure even distribution of garlic and even cooking
continue to cook in 3-minute increments, tossing vegetables every 3 minutes until evenly browned and almost entirely cooked through.
The whole process should take roughly 22-30 minutes.
Remove roasted and browned vegetables before they become soft and overcooked and let them cool.
Cauliflower will generally take longer than the broccoli, depending on how it is cut.
Mix your roasted vegetables in with your lemon zest, lemon juice, chopped olives, and finely-sliced cornichons.
Season with salt, freshly ground black pepper, and a pinch of cayenne pepper.
Add more freshly-squeezed lemon juice if necessary.