Toss the cauliflower florets with 1 tablespoon of the grapeseed oil and some salt and pepper. Transfer to a baking sheet and roast until tender and browned, 5 minutes. Set aside.
Heat the remaining 1 tablespoon grapeseed oil in a pan. Add the shrimp and garlic. Then add the chile flakes, capers, chicken stock, parsley and lemon juice. Cook for 3 to 4 minutes to cook the shrimp and build the sauce. Remove from the heat and whisk in the butter to emulsify the sauce.