Steps
1. Peel and chop the purple potatoes into cubes.
2. Boil the potatoes in salted water until tender, about 15 minutes.
3. Drain the potatoes and mash them with butter, garlic (minced), salt, and pepper until smooth.
4. Heat olive oil in a pan over medium-high heat.
5. Season the tuna steak with salt, pepper, and lemon juice.
6. Sear the tuna for 2-3 minutes on each side for medium-rare, or longer to desired doneness.
7. Plate the mashed purple potatoes and place the seared tuna on top.
8. Garnish with freshly chopped parsley and a drizzle of olive oil.
9. Serve immediately.