Cinnamon Sugar Snack Cake

Preheat oven to 350 degrees F (175 degrees C) and position rack in center of oven. Coat a 9-inch square baking pan with cooking spray. Line bottom of pan with parchment paper and coat parchment with cooking spray. (5 minutes)

Whisk together flour, baking powder, 1 teaspoon cinnamon, and salt in a medium bowl. (3 minutes)

In the bowl of a stand mixer fitted with a whisk attachment, mix together oil and butter. Mix in 1/2 cup white sugar and the brown sugar until well combined. Add eggs, one at a time, mixing well to incorporate and scraping bowl well after each addition. Mix in 2 teaspoons vanilla. (8 minutes)

Add about 1/3 of flour mixture; mix at low speed until combined. Mix in half of buttermilk, scraping bowl well. Repeat, alternating between flour mixture and buttermilk, until both are fully incorporated and batter is smooth. (5 minutes)

Pour batter into prepared pan and spread in an even layer. Stir together remaining 1/3 cup white sugar and 1 1/2 teaspoons cinnamon in a small bowl. Sprinkle cinnamon sugar evenly over batter. Wash and dry stand mixer bowl and whisk attachment. (5 minutes)

Bake until a toothpick inserted into center comes out clean or with a few moist crumbs, 20 to 25 minutes. Transfer pan to a wire rack and let cool completely.

For frosting, in bowl of stand mixer fitted with whisk attachment, beat cream cheese at medium speed 1 minute. Add powdered sugar and beat at medium speed until well combined. Scrape bowl well.

With mixer running at medium-low speed, add cream and remaining 1 1/2 teaspoons vanilla in a slow, steady stream. Gradually increase speed to medium-high and beat to medium peaks, 2 to 3 minutes more.

Fit a disposable pastry bag with a large round or star tip (about 1/4-inch wide). Fill bag with frosting.

Run a small offset spatula or a knife around outside of cake and gently invert onto a cutting board. Remove parchment paper. Cut into 9 squares.

Pipe frosting onto each cake piece: Starting at one corner of a square, pipe zigzag diagonally, ending at opposite corner. Repeat with remaining squares. Garnish with cinnamon. Chill in an airtight container until ready to serve, up to 4 days.