Step 1: Make cake batter
In the bowl of a stand mixer fitted with the paddle attachment, cream together butter and sugars. Add egg and Pure Madagascar Vanilla Extract and mix until combined. In a separate bowl, combine flour, baking powder, and Frosted Cinnamon Bun Popcorn Seasoning. Alternate adding 1/3 dry ingredient mixture and buttermilk to wet ingredient mixture and stir until just combined. Scrape down sides of bowl, making sure no flour remains. Transfer to a separate bowl and set aside.
Step 2: Make cream cheese frosting layer
In the bowl of a stand mixer fitted with the paddle attachment, beat cream cheese and Pure Madagascar Vanilla Extract together until fluffy. Add egg and mix until combined. Add powdered sugar and mix until well-combined and no clumps remain. Set aside.
Step 3: Make streusal topping
In a small bowl, combine brown sugar, flour, Frosted Cinnamon Bun Popcorn Seasoning, Ground Cardamom, and butter. Pinch the butter into the dry ingredients with your fingers until mixture reaches a breadcrumb consistency.
Step 4: Assemble
Preheat oven to 350 degrees. Line an 8x8 pan with parchment paper and grease well. Spread half of the cake mixture over the bottom of the pan. Add a thin layer of streusal topping. Cover this layer with all of the cream cheese frosting mixture. Add a thin layer of streusal topping. Cover this layer with remaining cake mixture. Sprinkle generously with streusal topping mixture, ensuring entire surface is covered.
Step 5: Bake
Bake at for 40 to 45 min., rotating halfway through, until top is golden brown and a toothpick inserted into the center comes out clean. If top of cake is browning too quickly, cover with foil for the remainder of the baking time.