Rinse all of your strawberries (do not cut the tops off) and place them on a plate lined with paper towels and set them aside to dry completely.
Preheat the oven to 350 degrees. Then mix all your cake ingredients, brownie mix, water, oil, eggs and sour cream, together in a large mixing bowl until combined.
Next, spray a muffin tin with non-stick cooking spray and pour the brownie batter evenly among each tin and bake for 20-25 minutes or until a toothpick comes out clean from the center of each brownie. Place the brownies on a cooling rack to cool.
While the brownies are baking, prepare your strawberry buttercream by creaming the softened butter using a hand or stand mixer. Add your strawberry jam and combine with the butter.
Throw in a pinch of salt, then start adding the powdered sugar one cup at a time, combining as you go. Once the buttercream is finished, add to a piping bag.
Pipe the buttercream onto each brownie and top with a tablespoon of diced strawberries around the rim of the buttercream.
Next, melt the melting chocolate in a microwave safe bowl, according to the package instructions, and dip each strawberry in one at a time, placing each one on top of each frosted brownie as you go.