Food & Cooking Recipes Dessert & Treats Recipes Cake Recipes Orange-and-Poppy-Seed Sheet Cake Be the first to rate & review! By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on January 20, 2021 Print Rate It Share Share Tweet Pin Email Photo: Con Poulos Prep Time: 20 mins Total Time: 2 hrs 20 mins Yield: 10 to 12 Serves Full of citrus flavor, this recipe includes orange zest, sour cream, poppy seeds, and vanilla paste in the batter and orange juice in the luscious, easy icing. To serve, shower with more poppy seeds and get creative when cutting: Small and large planks, slices on the bias, and even triangles are fair game when it comes to a sheet cake. Ingredients Cake 1 stick unsalted butter, melted and cooled, plus more, softened, for pan 1 ⅔ cups unbleached all-purpose flour 2 teaspoons baking powder ¾ teaspoon kosher salt (we use Diamond Crystal) 4 large eggs, room temperature 1 ½ cups granulated sugar 1 tablespoon finely grated orange zest 2 tablespoons poppy seeds 2 teaspoons pure vanilla paste or extract ¾ cup sour cream, room temperature Icing 2 cups confectioners' sugar, sifted 1 tablespoon unsalted butter, melted 1 tablespoon fresh orange juice 1 teaspoon poppy seeds Directions Cake: Preheat oven to 350°F. Brush a 9-by-13-inch or 8-by-12-inch baking pan with butter. Line with parchment, leaving a 2-inch overhang on long sides. Butter parchment. Whisk together flour, baking powder, and salt. Combine eggs and sugar in the bowl of a mixer fitted with the whisk attachment. Beat on high speed until thick and pale, about 4 minutes. Add flour mixture; beat to combine. Add butter, zest, poppy seeds, and vanilla; beat to combine. Add sour cream; beat until smooth. Scrape batter into prepared pan, smoothing top with a spatula. Bake until top springs back when lightly touched and a tester inserted in center comes out clean, 30 to 35 minutes (for 9-by-13-inch) or about 40 minutes (for 8-by-12). Let cool in pan on a wire rack 10 minutes. Using parchment overhangs, lift cake out of pan and let cool completely on rack. (Cake can be made to this point and stored at room temperature, wrapped in plastic, up to 1 day.) Icing: Whisk together confectioners' sugar, butter, and orange juice until smooth. Spread over cake. Sprinkle with poppy seeds. Let set at least 20 minutes before serving. Iced cake can be stored in an airtight container at room temperature up to 3 days. Cook's Notes Leftovers will last about three days at room temperature in an air-tight container. Rate it Print