The humble potato: poor man's dish or the king of roots?

It’s beef tenderloin time tonight. Letting it sizzle in butter (or ghee) for the briefest of moments just to get a semi-burnt crust on both sides, leaving the interior tender and juicy and quite red, still dripping with blood. (I know it’s not to everyone’s liking, but I can’t help myself. I’m a confirmed meat-eater – the fresher the better. A properly served Steack à la tartare will invariably take me to heaven and has occasionally led me to experience la p’tite mort.)

What better to accompany the tenderloin than the simple spud? But prepared how? I’m struggling, like I do every single time I want to use potatoes, to make a decision between four delicious recipes, herbs and seasoning excluded:

Diced and fried (standard Swedish way, but without sliced onion)
Sliced and oven baked in a cream bath, topped with breadcrumbs and melted cheese (classic French Gratin)
Boiled and mashed with butter and a raw egg or two. I never use milk or, god forbid, water! Whipping cream will do at a pinch as a butter substitute, but never, ever skip the egg. (potato mash à la Nenad)
Thinly sliced and gently sautéed in butter, together with sliced onion and a pinch of crushed garlic, until it starts coming apart. (my grandmother’s recipe for ‘restovan krompir’, a classic Balkan recipe)

Which one is your favourite?