Coulibiac of Salmon with Pickled Beets and Kale

Preheat oven to 375°F with rack positioned in lower third of oven. Heat oil in a large skillet over medium. Add garlic, and cook, stirring constantly, until just beginning to brown, about 1 minute. Add kale, 1/2 teaspoon salt, and 1/2 teaspoon pepper. Cook, stirring constantly, until kale is wilted, 2 to 3 minutes. Transfer to a medium bowl; let cool 15 minutes. Squeeze kale mixture in paper towels to drain excess liquid. Set aside.

Stir together rice, lemon zest, 3/4 teaspoon salt, and 1/4 teaspoon pepper in a medium bowl. Stir together crème fraîche, dill, capers, caper brine, lemon juice, and salt and pepper to taste in a second medium bowl. Set both aside.

Trim salmon fillet lengthwise to form a 9- x 4-inch rectangle of even thickness; reserve scraps for another use. Sprinkle salmon with remaining 1/4 teaspoon salt and remaining 1/4 teaspoon pepper. Spread mustard evenly over top of salmon; set aside at room temperature.

Unfold phyllo sheets, and place on a work surface; cover with a damp towel to prevent them from drying out. Place 1 phyllo sheet on a parchment paper–lined baking sheet, and brush top lightly with melted butter. Top with a second phyllo sheet to create a neat stack. Brush top of second sheet lightly with melted butter. Continue stacking, brushing each layer with butter, until stack is 6 sheets thick. Do not brush top of last sheet. Cover stack with a damp kitchen towel. Repeat process of stacking and brushing with butter to form a second stack of 4 phyllo sheets; cover stack with a damp towel. Cover and reserve remaining phyllo sheets and melted butter.

Uncover stack of 6 phyllo sheets on the baking sheet. Spread rice mixture lengthwise in a 9- x 4-inch rectangle of even thickness (about 3/4 inch thick) in center of phyllo stack. Top with salmon. Arrange beet slices, slightly overlapping, on salmon. Top with kale in an even layer.

Fold edges of phyllo base up around filling to form a boat shape, pleating as needed. Place stack of 4 phyllo sheets lengthwise on top of filling, and fold down, tucking edges under coulibiac. Re-melt butter, if needed. Brush top and sides of coulibiac with melted butter, reserving about 2 tablespoons for drizzling.

Working with 1 phyllo sheet at a time, scrunch up sheet, and place on top of the coulibiac with edges sticking up randomly in all directions, like tissue paper. Repeat with remaining 4 phyllo sheets, arranging and tearing as needed to completely cover the top of the coulibiac. Drizzle remaining 2 tablespoons butter over top.

Bake in preheated oven until golden brown and crispy and a thermometer inserted in salmon through side of coulibiac registers 140°F, about 30 minutes, tenting with aluminum foil after 15 minutes to prevent excess browning. Let cool on baking sheet 10 minutes. Using a serrated knife, cut crosswise into 6 even portions. Garnish with dill, and serve with crème fraîche sauce.