Preheat oven to 350 degrees F.
Line a muffin pan with paper cupcake liners, set aside.
In a mixing bowl, combine the flour, baking powder, and salt. Set aside.
In a separate mixing bowl, combine the sugar and butter, with a hand mixer mix until creamed together (1-2 minutes).
Add the sour cream, milk, and vanilla extract and mix until creamy and no lumps remain.
Then mix in one egg at a time until well combined.
Add the flour mixture and stir with a wooden spoon. A thick dough like batter will form.
Scoop even portions of the batter into each cup of the prepared muffin pan (about 1/8 cup each, or halfway full each).
Place pan in the oven and bake for 19-22 minutes, or until cake remains firm when you gently press it with your finger.
Remove from oven and transfer to a cooling rack and allow to cool completely before decorating.
To make the strawberry filling, cut strawberries into small pieces and place in a bowl. Add the sugar and lemon juice, mix, and set aside.
To make the whipped topping, on a mixing bowl, add heavy cream, powder sugar, and vanilla extract and mix with a hand mixer on medium high speed until stiff peaks form (about 3-5 minutes).
Transfer whipped topping into a piping bag and set aside.
Once the cupcakes have cooled, using a spoon or a cupcake corer, remove about 1 Tablespoon of cake from the center of each cupcake.
Fill with 1 Tablespoon of strawberry filling (don’t be afraid to let a little bit of the juices from the strawberries get in there!), then pipe the whipped topping on top of each cupcake.
Top with optional strawberries and serve immediately.