PreparationFor topping: Preheat oven to 350°F. Place sugar and butter in 9-inch-diameter metal cake pan with 3-inch-high sides. Whisk over medium heat until sugar dissolves, butter melts, and sauce is bubbling thickly, about 3 minutes. Whisk in lemon juice and salt. Remove from heat and cool 5 minutes. Arrange date quarters in 3 concentric circles in caramel, rounded side down, covering completely. For cake: Sift first 4 ingredients into medium bowl. Using electric mixer, beat butter and both sugars in large bowl until light and fluffy. Beat in vanilla, then eggs, 1 at a time. Beat in dry ingredients in 3 additions alternately with buttermilk in 2 additions. Spoon batter over topping in pan. Place cake pan on large baking sheet. Bake cake until puffed and golden and tester inserted into center comes out clean, about 50 minutes. Cool cake in pan on rack 15 minutes. Cut around pan sides and invert warm cake onto platter. Carefully lift off pan. Return any dates that stick to pan to top of cake. Scrape any caramel left in pan over cake. Serve cake warm or at room temperature with whipped cream.
PreparationFor topping: Preheat oven to 350°F. Place sugar and butter in 9-inch-diameter metal cake pan with 3-inch-high sides. Whisk over medium heat until sugar dissolves, butter melts, and sauce is bubbling thickly, about 3 minutes. Whisk in lemon juice and salt. Remove from heat and cool 5 minutes. Arrange date quarters in 3 concentric circles in caramel, rounded side down, covering completely. For cake: Sift first 4 ingredients into medium bowl. Using electric mixer, beat butter and both sugars in large bowl until light and fluffy. Beat in vanilla, then eggs, 1 at a time. Beat in dry ingredients in 3 additions alternately with buttermilk in 2 additions. Spoon batter over topping in pan. Place cake pan on large baking sheet. Bake cake until puffed and golden and tester inserted into center comes out clean, about 50 minutes. Cool cake in pan on rack 15 minutes. Cut around pan sides and invert warm cake onto platter. Carefully lift off pan. Return any dates that stick to pan to top of cake. Scrape any caramel left in pan over cake. Serve cake warm or at room temperature with whipped cream.