To prepare the crumble:

1. In a small bowl, stir together the butter and lemon juice. Add the sugar and salt, stirring to combine. Fold in the flour until large clumps form. Place in the fridge to chill while you prepare the cake.

To prepare the cake:

1. Preheat the oven to 350 degrees. Spray a 9” springform pan with baking spray and set aside.
2. In a large bowl or the bowl of a stand mixer, cream the butter and sugar together on medium speed until smooth, about 2 minutes. Add the eggs, vanilla, and lemon zest and beat to combine. Scrape the sides of the bowl and add ½ cup of the flour, the baking powder, the baking soda, and the salt. Stir on low to barely combine. Stir in the buttermilk and then add the remaining flour on low speed just until integrated. Scrape the sides of the bowl and fold in any unincorporated batter.
3. Spread about 2/3 of the batter into the bottom of the springform pan. Smooth the preserves over top pf the batter, leaving a 1” border around the perimeter of the cake. Carefully spread the remaining batter on top and sprinkle the whole thing with the crumble, breaking up the big clumps into a crumb size you prefer. Bake in the preheated oven for about 35-40 minutes, or until the top is puffed and a toothpick inserted comes out clean. Set aside to cool.

To prepare the glaze:

1. When you’re ready to prepare the glaze, whisk together all the ingredients until a viscous glaze forms. Add more powdered sugar to thicken it up and more sour cream or lemon juice to thin it out. Drizzle over top of the prepared cake and enjoy!