Make the Kale Pesto: Remove the central tough stem from each leaf, and stack the leaves and thinly slice.Throw into the food processor along with the other ingredients except the olive oil. Process until finely chopped.Drizzle the olive oil into the processor bowl, while running the food processor, until you get the consistency you prefer.
If storing, pour into a jar and cover with more olive oil. It can be kept in the refrigerator for up to two weeks.
Make the Chipotle Spice Rub and Brown Butter Breadcrumbs, and set aside.
Preheat the oven to 400° F. Slice the cauliflower head in half through the central stalk. Slice each half into two halves. You should have 4 thick cauliflower slabs. Some florets will crumble off the slabs towards the ends. Don't throw them out.
Rub both the slabs and florets with olive oil and the Chipotle Spice Rub.
Heat some olive oil in a sautè pan over medium-high heat, and sear the cauliflower slabs until slightly crisped - about 3 minutes per side.
Place on a baking sheet along with the florets, and roast until tender, about 15 minutes.
Make the Citrus Salad: Combine the citrus, shallot, olives and the roasted cauliflower florets in a small bowl.
Make the dressing by whisking together the vinegar and spice rub together. Drizzle in the olive oil as you continue to whisk. Toss with the citrus salad.
To Serve: spoon the citrus salad onto a serving plate. Lay the cauliflower steaks over the salad. Spread the kale pesto over the steaks, and sprinkle on the breadcrumbs.