Preheat the oven to 375°F and grease a 9-inch springform cake pan, and line the bottom with a circle of parchment paper.

In a stand mixer using the paddle attachment, combine the butter, white and brown sugar, vanilla, and the salt on high, until mixed and lightly fluffy. Add the eggs one at a time—fully incorporate the first egg before adding the next. Add in the sour cream 1/4 cup at a time and mix until incorporated, then the apple cider vinegar and 1 Tbsp oil—mix until smooth.

In a medium bowl, combine the white flour, spelt flour, and baking powder. Add half of the dry mixture to the wet ingredients on a low speed. Scrape the sides of the bowl and paddle if needed, then add the remaining dry ingredients and mix on low speed until combined and smooth—don’t over-mix.

Fan out the slices of 1 apple onto the bottom of the pan with a sprinkle of brown sugar, then pour in the batter and smooth the top. Fan out the remaining apple around he edges, then sprinkle the top with the almonds and brown sugar—make sure the almonds are mostly covered so they don’t burn.

Bake for 40-45 minutes, or until the cake is golden and a tester inserted into the center comes out clean.

Remove the pan from the oven and move to a cooling rack. Allow the cake to cool for 20 minutes, then unmold by scraping a knife around the edges and releasing the sides.

Serve for dessert or brunch with whipped cream or vanilla ice cream.