Preheat oven to 350 °F. Grease a 9-inch round baking pan and/or line with parchment paper and set aside.
In a large bowl, combine flour, sugar, brown sugar, cocoa powder, baking powder, baking soda, and salt.
In a separate bowl, whisk together eggs, sour cream, oil and vanilla extract until smooth. Add to dry ingredients and fold together until fully incorporated and no dry spots are in the batter.
In a cup or a small bowl, heat ½ cup of milk in the microwave for 1 to 1 ½ minutes, until slightly hot. Add espresso powder and whisk together. Pour into cake batter and continue to mix together until batter is uniform.
Pour batter into cake pan and bake for 40-45 minutes, until a toothpick comes out clean.
While cake is baking, cut up strawberries and pour sugar and lemon juice on top. Toss together and add to the refrigerator. Then make the whipped cream by adding heavy whipping cream and sugar to a large bowl and beating until stiff peaks form. (about 2-3 minutes) Fold in vanilla extract and pinch of salt and add to refrigerator until ready to use.
Once cake is done, let the cake cool for 5 minutes then remove the cake from the pan. Allow it to cool completely. Then add whipped cream and strawberries on top. Garnish with mint, optional