Saumon en Papillote au Beurre Blanc with Buttered Spinach

Preheat the oven to 200°C. Cut four large rectangles of parchment paper and divide the julienned leek among them, creating a bed in the center of each piece.

Place a salmon fillet on each leek bed, season with salt and pepper, lay a dill sprig and a few lemon slices on top, then drizzle a small amount of white wine over each fillet. Fold the parchment over the salmon and crimp the edges tightly to seal completely.

In a small saucepan, combine the minced shallot, white wine vinegar, and dry white wine over medium heat. Simmer until the liquid reduces to about 2 tablespoons, approximately 5-7 minutes, stirring occasionally.

Place the sealed parcels on a baking sheet and transfer to the preheated oven at 200°C. Bake for 14-16 minutes until the parcels puff up dramatically, indicating the salmon is cooked through.

Melt butter in a large skillet over medium heat at 165°C. Add minced garlic and cook for 30 seconds until fragrant. Add spinach in batches, turning with tongs until just wilted, about 2 minutes total. Season with salt, pepper, and a grating of nutmeg, then squeeze out excess liquid and keep warm.

Reduce the heat under the saucepan with the wine reduction to very low, around 80°C. Whisk in the cold butter one cube at a time, ensuring each piece melts fully before adding the next, and never let the sauce boil. Season with salt once emulsified and keep warm off the heat.