Preheat the oven to 325°F. Spritz 9 cups of a standard muffin tin with cooking spray. Set aside.
Prepare brownie mix using amounts called for on the package for water, oil and eggs. Add to a medium-size mixing bowl. Mix using an electric mixer or by hand, until fully combined.
Divide brownie batter filling muffin cups approximately ⅔ full. (Note: Yield may vary slightly depending on how the batter is divided.)
Bake for 25-30 minutes or until a toothpick inserted into the center shows moist crumbs. Remove to a cooling rack. Cool in the pan to warm, then carefully remove.
Meanwhile, toss strawberries with granulated sugar, gently stir and allow the strawberries to macerate. Chill until assembling.
Using an electric mixer, whip cream on medium-high gradually adding sugar. Whip until stiff peaks form, then chill until assembling.
To assemble, place one brownie cupcake on a serving plate. Top with sweetened fresh whipped cream and cubed strawberries. Drizzle with chocolate sauce. Top with an additional dollop of whipped cream. Garish with one whole strawberry.