Preheat your oven to 350°F (175°C) and grease a cake pan.
In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, and salt.
Add water, vegetable oil, and vanilla extract to the dry ingredients and mix until smooth.
Pour the batter into the prepared cake pan and bake for 30 minutes, or until a toothpick comes out clean.
Allow the cake to cool completely before removing it from the pan.
In a separate bowl, whip the heavy cream with 2 tablespoons of sugar until soft peaks form.
Frost the cooled cake with whipped cream and arrange sliced strawberries on top.