I've posted on this recipe before so pardon me if you've been around this forum a long time and know the Joel Robuchon recipe which I've expressed love for before, but I made one again last night. This time though, a huge one in an oval baking dish. Cooking for a crowd with a French Country theme, I scaled the recipe up, way up, and used a large oval baking dish, one and a half pounds of bacon, almost 5 pounds of potatoes and 2 cups of swiss cheese.
But there's no way to scale it up exactly--just have enough ingredients at the ready. Vessel shape matters, so does the thickness of your bacon. I bought two pkgs of thin Oscar Meyer bacon but one pkg was somehow cut just a little thicker and got less good coverage than the other. Btw, I never thought the six ounces of bacon in the original recipe enough for even the base recipe, it never came close to lining the gratin as shown in the book's photo (not a shock, such is the 'lie' of food photography). Something to consider if using more bacon like I did, with more bacon bringing in fat you don't need as much cheese (or salt). That is, for this gratin I used about 24 ounces of bacon--400% of the original!, but not even 200% of the cheese.
Look how great it turned out!
Here's my old post on the original recipe, done to the original size (serves four):
As main course gratins go, I've never had better. And could it be simpler? Just four ingredients. Here's my original post on the recipe.
1 tblsp clarified butter (didn't use any, as I used a lot more bacon)
6 oz thinly sliced bacon, trimmed of excess fat (I used 12 ounces of center cut)
2.5 lbs baking potatoes (I used five medium russets)
1 1/4 c grated Gruyere cheese (I used Emmenthaler)
Black pepper to taste
Preheat the oven to 425 F.
Drizzle the olive oil or butter in the bottom of a baking dish. I used an 8 inch round, two quart gratin dish.
Arrange the bacon in the baking dish so that the pieces will line the inside edge and extend outward away from the dish. Arrange one third of the potato slices in the bottom, then sprinkle with a third of the cheese and a grind of black pepper. Repeat two more times, then fold the overhanging bacon back onto the potatoes. Plan it so that the bacon covers all but a 2" venting hole in the center. Bury any extra or lean trim pieces underneath the folds of bacon or fill any gaps--no need to waste it, and it all turns crisp.
Bake uncovered until the potatoes offer no resistance when pierced with a knife, about 50 minutes. Remove from the oven and pour off the accumulated bacon grease, then allow to rest about 15 minutes. The potato cake can be unmolded to serve or cut into pie wedges and served straight from the dish.
