Brown Sugar Sheet Cake

Brown Sugar Sheet Cake 3 cups all-purpose flour 1 3/4 cups brown sugar 3/4 cup sugar 1 1/2 cups (3 sticks) unsalted butter, room temperature 3 eggs, lightly beaten 3/4 cup greek yogurt 3 teaspoons vanilla extract 1 1/2 teaspoons baking soda 1 teaspoon salt Icing: 4-6 cups powdered sugar, as needed 1 1/2 cups dark brown sugar 3/4 cup (1 1/2 sticks) unsalted butter 1/2-1 cup whole milk, warmed 1 teaspoon vanilla extract 1/2 teaspoon salt Preheat oven to 375º F and line a baking sheet (jelly roll pan) with butter or parchment paper. In a medium bowl, whisk together flour, baking soda and salt, and set aside. In a large bowl or mixer, cream butter and sugars (white and brown) together until fluffy and lightened in color. 2-3 minutes. Beat in eggs and vanilla extract until incorporated, then mix in greek yogurt. Once combined, add in dry ingredients. Be careful not to overmix. Pour batter into greased and/or lined baking sheet and place in oven. Bake for 17-20 minutes, or until toothpick inserted in center comes out clean. Remove from oven and let cool 5 minutes. Prepare icing: in a medium or large saucepan, whisk together butter, brown sugar and 1/2 cup milk over medium-high heat. Bring mixture to a boil, then remove from heat. Stir in 4 cups powdered sugar (to start), vanilla extract and salt, stirring until smooth and thickened. (Add more powdered sugar, if desired.) Pour over cake and let set.