For the Chocolate Brownie Cake:

1. Preheat the oven to 350°F (175°C).
2. Line a 9×13-inch baking pan with parchment paper, allowing some overhang if desired, for easy removal. Grease the parchment paper.
3. In a medium saucepan, melt the butter over medium heat. Once melted, remove from heat and add sugar. Stir until combined.
4. Add eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
5. In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt. Gradually add to the butter mixture, stirring until fully incorporated.
6. Pour the batter into the prepared baking pan and spread evenly.
7. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Allow to cool completely in the pan on a wire rack.

For the Chocolate Ganache Frosting:

1. In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer. Do not let it boil.
2. Place the chopped chocolate in a heatproof bowl. Pour the hot cream over the chocolate and let sit for 2 minutes. Stir until smooth and fully combined.
3. Add the butter and stir until melted and the ganache is glossy. Set aside.

For the Pumpkin Patch Decorations: 

1. Wash and thoroughly dry the strawberries. Line a tray with parchment paper.
2. Melt the orange candy melts in a double boiler or according to packaging instructions.
3. Hold each strawberry by the stem and dip into the melted candy, coating it completely. Place on the prepared baking sheet to set.

Final Steps:

1. Remove the cooled brownie cake from the pan using the parchment overhang. Spread the chocolate ganache frosting evenly over the top.
2. Place the dipped strawberries on top of each brownie piece, pressing slightly to secure. Arrange mint leaves around the strawberries to create the look of a pumpkin patch.
3. Cut the frosted brownie cake into squares or rectangles to resemble individual brownies.
4. Serve immediately or store in an airtight container at room temperature for up to 3 days. Enjoy your festive Chocolate Pumpkin Patch Brownie Cake!