Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, beat together butter and sugar until light and fluffy.
Add eggs, one at a time, then stir in vanilla extract.
Gradually add dry ingredients, alternating with buttermilk, starting and ending with dry ingredients. Mix until just combined.
Fold in diced strawberries gently.
Fill cupcake liners 2/3 full with batter.
Bake for 18-20 minutes or until a toothpick comes out clean.
Cool cupcakes on a wire rack.
Whip heavy cream with powdered sugar and vanilla until stiff peaks form. Frost cooled cupcakes with whipped cream and top with fresh strawberries.