Step 1

Preheat the oven to 350°F. Spray an 8×8 square baking dish with baking spray, and set aside.

Step 2

In a medium bowl, stir together the flour, baking powder, baking soda, and salt, and set aside.

Step 3

In the body of a stand mixer with the paddle attachment (or in a large bowl with an electric mixer), cream the butter, oil, and sugar together until light and fluffy, 3 minutes on medium speed.

Step 4

Add the egg yolks and egg one at a time, mixing the first one in fully until adding the next. Stir in the vanilla and almond extract.

Step 5

Add half of the flour mixture and mix it in. Add half of the buttermilk, and stir it in until combined. Repeat with the remaining flour and buttermilk, and scrap down the sides of the bowl as needed.

Step 6

Spread the batter into the prepared pan. Bake for 26-28 minutes until light golden brown and it begins to pull away from the sides, a toothpick inserted into the center will come out clean, a few moist crumbs are okay, but any wet batter and it needs longer. Cool cake in the pan completely on a wire rack.

Step 7

Next, make the filling. Place the cornstarch, salt, and egg yolks into a medium-sized bowl and whisk until combined, set aside.

Step 8

Place the milk and sugar into a small saucepot and stir to combine. Place over medium heat, constantly stirring until it comes to a simmer. Once at a simmer, very slowly stream the milk mixture into the egg yolk mixture, constantly whisking until fully combined.

Step 9

Pour the mixture back into the pot. Stirring constantly, bring to a boil.

Step 10

Take off the heat and stir in the butter, vanilla, and almond extract.

Step 11

Place a fine mesh strainer over a large mixing bowl. Pour the filling through the strainer and press it through to get any lumps out. Place a piece of plastic wrap touching the filling on top. Place in the fridge for 2 hours to chill completely.

Step 12

For the almonds, line a sheet tray with parchment paper, and set aside. Place the almonds on the sheet tray in a single layer. Bake for 18 minutes, tossing the nuts around every 3 minutes.

Step 13

Place the nuts into a large bowl. Add the water and sugar, and stir to combine. Place them back on the sheet tray in a single. Continue to bake for 12-15 minutes, stirring every 3 minutes until they reach your desired toastiness. Immediately transfer them to a cold sheet tray to cool, or they will continue to toast.

Step 14

For the frosting, in a large bowl with an electric hand mixer, whip the butter until smooth. Add the powdered sugar a little at a time until fully combined.

Step 15

Add the salt, vanilla, almond extract, and milk, and stir until combined. Place on medium-high speed and whip for 3 minutes until light and fluffy.

Step 16

Once the cake is completely cooled, and the filling is chilled, assemble the cake. Take the cake out of the pan and cut it in half lengthwise. Place one of the cake layers on the bottom of your cake plate or serving platter.

Step 17

Smooth the filling on top, leaving a ½-inch border. Place the top of the cake on top, press down gently.

Step 18

Add a thin layer of frosting on the top and sides of the cake for a crumb coat. Place in the fridge for 1 hour to set.

Step 19

Add the remaining frosting to the outside of the cake. Take the almonds and press them all over the cake into the frosting so it will stick. Serve immediately.