Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Peel and cube the sweet potato into small 1/2-inch pieces.
In a large bowl, toss the cauliflower florets and sweet potato cubes with 0.5 tbsp of olive oil and half of the sea salt, black pepper, and garlic powder.
Spread the vegetables in a single layer on the baking sheet and roast for 20-25 minutes until the cauliflower is caramelized and the potatoes are tender.
While the vegetables roast, season the sirloin steak on both sides with the remaining sea salt, black pepper, garlic powder, and smoked paprika.
Heat the remaining 0.5 tbsp of olive oil in a cast-iron skillet over medium-high heat until shimmering.
Place the steak in the skillet and sear for 3-4 minutes per side for medium-rare, or until it reaches your desired doneness.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes before slicing it into thin strips against the grain.
Assemble the bowl by placing the roasted vegetables at the base and arranging the steak strips on top.
Slice the avocado and place it on the bowl, then garnish with freshly chopped parsley before serving.