Step 2

Preheat the oven to 425°F. Have ready a 10-inch cast-iron skillet (or other oven-safe skillet).

Step 3

Place the potatoes in a large bowl. In the skillet, melt the butter over medium heat. Add the garlic and cook until fragrant (but don't let it brown!), about 1 minute. Swirl the butter to evenly coat the whole skillet, then pour it over the potatoes.

Step 4

Gently stir the potatoes to coat evenly with the butter. Season with the salt and pepper, and toss well to combine.

Step 5

Starting in the center of the skillet, start to arrange the potatoes in a spiral, overlapping each slice slightly and trying to keep it as even and level as possible.

Step 6

Once you fully cover the base of the skillet, sprinkle some of the Parmesan evenly over the potatoes. Start another layer of potatoes, repeating steps 4 and 5 until you've used all the potatoes and cheese. Try to keep the layers as even as possible.

Step 7

Sprinkle more grated Parmesan over the surface of the assembled galette, if desired. Transfer the galette to the oven and bake until it can be easily pierced through the center with the tip of a paring knife and the whole thing is deeply golden brown, 50 to 55 minutes.

Step 8

Remove from the oven and cool for 5 minutes. Run a small offset spatula around the edge of the potatoes, then flip onto a serving platter or cutting board. It should easily unmold, but if it sticks, use a spatula to loosen any stuck bits.

Step 9

Cool for 15 minutes more before finishing. To serve, spread the crème fraîche evenly over the surface of the potatoes, then layer the salmon on top. Garnish with the red onion, chives, dill and capers (if using).