Preheat your oven to 175°C (350°F) and grease a 9x13-inch cake pan with butter or non-stick spray.

In a large mixing bowl, beat together 1 cup of unsalted butter and 1 cup of granulated sugar until fluffy and lightened in color, about 3-4 minutes. Add in 1/4 cup of oil, 4 eggs, 1 cup of Greek yogurt, and 2 teaspoons of vanilla extract, mixing until well combined and smooth.

In a separate bowl, sift together 2 ½ cups of all-purpose flour, 1 teaspoon of salt, 2 teaspoons of baking powder, and 1 teaspoon of baking soda. Gently fold the dry ingredients into the wet mixture using a spatula until just combined.

Pour the cake batter evenly into your prepared pan, smoothing the top with a spatula. Bake in the preheated oven for about 35 minutes, or until a toothpick inserted in the center comes out clean.

While the cake bakes, prepare the pastry cream. In a medium bowl, whisk together 1/2 cup of granulated sugar and 4 egg yolks until combined. Heat 2 cups of whole milk in a saucepan until steaming but not boiling.

Gradually temper the egg mixture, then cook over medium heat, stirring constantly until thickened, about 5-7 minutes.

Once the cake is baked and slightly cooled, use the handle of a wooden spoon to poke holes all over the top of the cake. Pour half of the warm pastry cream into the holes.

Let the cake cool completely in the pan on a wire rack.

In a large bowl, whip 1 cup of heavy cream until it reaches soft peaks. Gently fold in the remaining pastry cream until fully combined.

Spread the diplomat cream evenly over the cooled cake, smoothing out the top and sides.

In a heatproof bowl, melt 8 ounces of semi-sweet chocolate together with 1 cup of heated heavy cream until smooth and shiny.

Once the ganache has cooled and thickened, pour it over the frosted cake, spreading it evenly.

Chill the finished Boston Cream Poke Cake in the refrigerator for at least 4 hours, or overnight, to set the ganache.