Yasmin Seneviratne is the founder of Le Sauce magazine, which features original recipes and stories about food.
Units: Metric US Imperial
Leek Cream Sauce
Heat butter and olive oil in small pan over medium heat. Add leeks and half the salt, stir, then reduce heat to low. Sauté until leeks are softened, stirring occasionally to ensure they don’t brown. Add remaining salt, cream and wine. Bring to low simmer and cook for a few minutes to heat sauce and allow to reduce slightly. Remove pan from heat and purée sauce in blender, small food processor or with immersion blender until fairly smooth. Add lemon juice and taste. Season with salt and more lemon juice if desired. Let cool.
Preheat oven to 375°F (190°C). Quickly roll dough out on a lightly floured surface with a lightly floured rolling pin. Dough should form an 11- x 18-inch (28 x 45 cm) rectangle so that it fits onto a baking sheet. Transfer to parchment-paper-lined baking sheet. Score 1/2-inch (1.27 cm) edge around rim of the rectangle and dock all over interior with a fork. Spread cooled sauce evenly over tart up to edges of scored rim. Lay chard leaves on top evenly (gaps are fine) and tear oyster mushrooms over top. Season lightly with salt. Bake for about 20 minutes, until edges of tart are golden. Remove, transfer tart on parchment to cutting board, slice into 8 pieces and serve as a main. Or cut into bite-sized pieces to serve as an appetizer either warm or at room temperature.