Remove leaves from cauliflower head, core, and cut into large bite-sized florets. Mince cilantro leaves and stems. Core Roma tomato and cut into 1/2" dice. Slice half the jalapeño into 1/8” rounds. Seed and mince remaining jalapeño. Zest and halve lime. Quarter one half and juice remaining half. Rinse chicken breasts, pat dry, and season both sides with 1/4 tsp. salt and a pinch of pepper.

Place cauliflower on prepared baking sheet. Drizzle with 2 tsp. olive oil, 1/2 tsp. salt, and 1/4 tsp. pepper. Toss to coat and spread into a single layer. Roast 10 minutes and remove from oven. Cauliflower will finish roasting in a later step. While cauliflower roasts, sear chicken.

Place a medium non-stick pan over medium-high heat. Add 2 tsp. olive oil and chicken to hot pan. Cook on one side until browned, 3-6 minutes. Flip chicken and sprinkle on half the seasoning blend (reserve remaining for garnish). Transfer to baking sheet with cauliflower, moving florets to one side to make room. Reserve pan; no need to wipe clean.

Place baking sheet in oven and roast until cauliflower is browned and tender and chicken reaches a minimum internal temperature of 165 degrees, 6-9 minutes. While chicken and cauliflower roast, make relish.

Return pan used to cook chicken to medium-high heat. When pan is very hot, carefully add 1 Tbsp. olive oil, tomatoes and minced jalapeños (to taste). Cook undisturbed until lightly charred, 1-3 minutes. Remove from burner and stir in lime juice, half the cilantro (reserve remaining for garnish), half the zest (reserve remaining for garnish), 1/4 tsp. salt, and a pinch of pepper.

Place cauliflower on plate and top with pepitas and remaining lime zest. Set chicken in front of cauliflower and garnish with remaining seasoning blend (to taste). Spoon tomato-jalapeño relish in front of chicken. Garnish dish with remaining cilantro, jalapeño slices (to taste), and lime quarters.