Preheat oven to 400°F (200°C).
Peel the sweet potato and slice into thick 1.5" slabs. Brush with avocado oil.
Roast on a parchment-lined baking sheet for 15 minutes. Flip each slice and continue roasting for another 15 minutes, or until tender but not mushy. Time may vary depending on your oven.
Roast the carrot alongside the potatoes until just tender, then slice into thin rounds for garnish.
Once baked, use the rim of a glass (smaller or larger depending on the size you want) to cut the potato slices into neat rounds.
Use a small spoon or melon baller to scoop a shallow well in each potato round.
Mash the avocado with lemon juice, olive oil, garlic, onion, and sea salt until smooth.
Pipe or spoon the avocado mixture into the wells of the potato slices.
Top each with a roasted carrot slice.
