Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Dice the sweet potato into small cubes, slice the carrots into rounds, and slice the baby marrows into thick half-moons.
Toss the sweet potato, carrots, and baby marrows on the baking sheet with 0.5 tsp of olive oil, half of the sea salt, and the garlic powder.
Roast the vegetables for 20-25 minutes, tossing halfway through, until they are tender and caramelized on the edges.
While the vegetables roast, season the steak on both sides with the remaining sea salt and the black pepper.
Heat the remaining 0.5 tsp of olive oil in a cast-iron skillet over medium-high heat until shimmering.
Place the steak in the hot skillet and sear for 3-4 minutes per side for medium-rare, or until it reaches your desired level of doneness.
Remove the steak from the skillet and let it rest on a cutting board for at least 5 minutes before slicing against the grain.
In the same skillet used for the steak, add the fresh spinach and sauté for 1 minute until just wilted from the residual heat.
Plate the meal by layering the wilted spinach, roasted vegetables, and sliced steak, then top with the cottage cheese and fresh avocado slices.