• 4 large Russet potatoes, scrubbed
  • Olive oil, for drizzling
  • Salt and pepper
  • 3 tablespoons butter
  • 3 onions, thinly sliced
  • 1/4 cup crème fraîche or heavy cream
  • 1 cup shredded Fontina Val d’Aosta or Gruyère
  • 1/2 cup grated Parmigiano-Reggiano cheese, a handful
  • 1 head broccoli cut into 4-inch long thin spears or 2 bundles broccolini, trimmed
Preheat oven to 400°F.
Rub potatoes with a little oil, season with salt and pepper and prick skins with a fork. Roast 1 hour, cool to handle. Halve the potatoes lengthwise down the center.
Heat a large skillet with a lid over medium heat. Add butter and melt; when it foams, add the onions and season with salt. Cover pan and cook 10 minutes, stirring occasionally. Uncover and cook 20 minutes more, stirring occasionally.  
Scoop the flesh of the potatoes into a bowl, leaving skins intact. Mash with salt, pepper, crème fraiche or cream and Fontina or Gruyère. Arrange the potato skins on a baking sheet and top with  
Coat the broccoli with a little olive oil, season with salt and pepper and roast to crispy at edges and tender, 20-25 minutes. Roast potatoes on another rack at same time until brown and bubbly.    
Serve the potatoes topped with roasted broccoli spears.