Preheat oven to 350°F. Line and grease an 8 inch cake pan; set aside.
In a medium bowl, whisk flour, cocoa powder, baking soda and salt together. Set aside.
In a large bowl, or in a bowl of a stand mixer fitted with the paddle attachment, combine butter and sugar until smooth and well combined.
Add egg and beat to combine thoroughly. Add oil, vinegar, vanilla buttermilk and food colouring. Beat until combined.
Add the dry ingredients and mix until just combined. You will see small lumps and that is okay.
Pour the batter into the prepared cake pan. Bake for 20 - 25 minutes, or until a toothpick inserted into the center comes out clean. Let cake rest for 10 minutes in the pan, and then turn out onto a wire rack to cook completely.
To make the whipped strawberry cream cheese, rinse and hull the strawberries. Place them into a small saucepan and over medium heat. Stir occasionally until strawberries become very soft. This will take about 15 minutes. Take the saucepan off the heat and mash strawberries with a potato masher.
In a medium bowl, combine cream cheese, powdered sugar, strawberry puree, and strawberry extract. Mix until well combined and smooth. Add the heavy cream and beat until smooth and fluffy, about 2 minutes.
To make the whipped cream, whip heavy cream until stiff peaks. I did not sweeten my whip cream as the other layers have enough sugar in them.
To assemble, cut the cake into 1 inch square pieces. Add a little less then half the cake pieces into the bottom of an 8 inch trifle dish. Top with half the amount of whipped strawberry cream cheese, and then half the amount of whipped cream. Repeat the layers and decorate the top with cake crumbs and extra strawberries.