Preheat oven to 350°F. Line a 9x13-inch pan with foil or parchment paper and spray with non-stick cooking spray.

In a large bowl, combine cake mix, melted butter, and eggs. Stir until just combined. This can be done by hand or with a mixer.

Press the batter evenly into the prepared pan. Bake for 15-20 minutes, or until lightly golden around the edges and no longer glossy. Let cool completely before frosting.

For the frosting: Beat the softened cream cheese with powdered sugar and vanilla extract until smooth. Gradually add the heavy whipping cream and beat on high speed until stiff peaks form.

Spread the frosting evenly over the cooled cake bars.

Just before serving, top the bars with the sliced strawberries.

Slice and serve immediately.