Preheat your oven to 425F.

Toss the potato and onion slices with melted butter and salt. Spread mixture onto an aluminum foil lined baking sheet and roast for 20-25 minutes, or until golden and tender, stirring once. Remove the pan from the oven and set aside.

To make the sandwiches, preheat your cast iron skillet or griddle over medium high heat. Butter both sides of the French bread slices and place the bread onto the hot skillet. Reduce the heat to medium and toast the bread on this first side for 3-5 minutes, until golden.

Reduce the heat to medium low and flip the bread slices to their second side. Evenly divide the Raclette cheese slices between all four pieces of bread.

Layer the roasted potatoes and onions on top of two of the pieces of bread.

Once the cheese is melted and the bread is toasted and golden on this second side (about 3-5 minutes), place the pickle slices and a kale leaf on top of the onions and top each sandwich with the other slice of toasted, cheese-laden bread.

Remove the sandwiches from the skillet and serve warm.