Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, leaving overhang on all four sides. Parchment paper may be held in place with binder clips, if necessary. Set aside.
In a medium bowl, combine dry crumb ingredients. Mix in melted butter. Use a fork to toss and combine ingredients until only small chunks remain. Set aside.
In a large bowl or stand mixer, beat together butter and sugar until light and fluffy. Mix in one egg at a time, followed by vanilla. Mix in lemon curd and optional zest, followed by salt, baking powder and baking soda. Alternate additions of flour and sour cream, mixing until just combined. Transfer batter to prepared baking pan. Use a small offset spatula to carefully spread out into an even layer. Generously sprinkle with crumb coating.
Bake for 40-50 minutes or until a toothpick inserted comes out clean. Cool completely on a wire rack.
When room temperature, carefully remove cake by pulling up and outwards on parchment paper. Transfer to a serving tray or platter.
In a small bowl, whisk together powdered sugar and lemon juice until smooth. Drizzle icing over cooled cake.
Slice and serve immediately. Store remaining cake in an airtight container for up to several days.
Notes
Homemade or store bought lemon curd may be used. Recipe serves roughly 9-12.An original recipe from Baked by Rachel
Nutritional information is provided as a courtesy and is an estimate only. Nutrition information can vary for a variety of reasons. For the most accurate data, use your preferred nutrition calculator with the actual ingredients you used to make this recipe.
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