Step 1

Preheat your oven to 175℃ / 350℉ (no fan) and grease a 9x13-inch / 22x33 cm pan or line it with parchment paper on the bottom and sides for easy removal.

Step 2

In a large bowl, cream the room-temperature butter and sugar for a few minutes until light and fluffy. Next, add the oil, and then the room-temperature eggs one at a time, mixing well after each addition. Then, mix in the room-temperature yogurt and vanilla extract.

Step 3

Sift the dry ingredients—flour, baking powder, baking soda, and salt—into the butter mixture. Gently fold them in with a rubber spatula until just combined. Be careful not to overmix the batter.

Step 4

Pour the batter into the prepared baking pan and smooth the top with an offset spatula. Bake for about 35 minutes at 175℃ / 350℉, or until a toothpick inserted into the center comes out clean. Be sure not to overbake it, as this can cause the cake to dry out.

Step 5

About halfway through the baking time, begin making the strawberry sauce by cooking the strawberry puree and sugar together for about 3 minutes. In a separate bowl, mix the cornstarch with water until smooth. Add a tablespoon of the warm strawberry sauce to the cornstarch mixture, then pour the cornstarch mixture into the strawberry-sugar mixture. Continue cooking for about a minute, stirring constantly, until the strawberry sauce thickens slightly.

Step 6

As soon as the sheet cake is done baking, take it out of the oven and use the handle of a wooden spoon to poke holes all over the top. Pour the strawberry sauce over the hot cake, making sure to focus on filling the holes. Set aside 1-2 tablespoons of sauce for later to use as decoration.

Step 7

Let the cake come to room temperature before frosting.

Step 8

Place very cold 36% fat-content heavy cream and cold 41% fat-content mascarpone into a mixing bowl, along with the sifted powdered sugar. Use an electric hand mixer to whip the mixture for about 2-3 minutes until fluffy.

Step 9

Once the sheet cake has cooled to room temperature, spread the frosting on top. To create the marble decoration, place dollops of strawberry sauce on top of the frosting and gently swirl it into the whipped cream. For the finishing touch, pipe additional whipped cream on top and garnish with strawberries.

Step 10

Serve the strawberry poke cake fresh. Any leftovers can be covered and stored in the refrigerator for 1-2 days.