CAKE:

Preheat oven to 350°. Grease and flour a 9x13 baking pan.

In a large bowl, whisk together the flour, sugar, baking powder, soda and salt.

In a second bowl whisk the oil with the buttermilk, eggs, egg yolks and vanilla. Add the wet ingredients to the dry ingredients and mix by hand just until the flour is combined. Pour it into the prepared pan and bake for 25-30 minutes. A toothpick should come out clean and the cake should be light golden brown.

JAM:

While the cake is baking, make the strawberry filling. Add strawberries, sugar, lemon juice and lemon zest to a saucepan and bring to a boil. Reduce heat to low and let it simmer until it thickens, about 10 minutes.

In a small bowl whisk the water with cornstarch and add to strawberries. Bring to a boil and cook for about 3 minutes so that the cornstarch can be absorbed. Remove from heat and mash the strawberries so that you have a fairly smooth mixture. You don’t want to have large chunks.

Remove the cake from the oven and let it cool for about 5 minutes on a wire rack. Then take the handle of a wooden spoon and poke large holes throughout the cake. While the cake and jam are both warm, spread the jam over the top, letting it go down into the holes. Let it cool completely on the counter and then refrigerate for about an hour so the jam can set.

FROSTING:

In a large bowl, beat the butter and cream cheese together with a hand mixer until smooth. Add powdered sugar and vanilla and beat until creamy.

Chop about ½ cup of fresh strawberries and mash with a potato masher, immersion blender or food processor. You want them to be pretty smooth. Once mashed, you should have 2 tablespoons of strawberries. Add them to the frosting and mix. Spread frosting on cake and refrigerate until set.