Begin by coating the wells of a 24-cavity mini muffin tin with a flour-infused baking spray to prevent sticking. Set the pan aside.

Adjust your oven rack to a position slightly above the center and preheat the oven to 325°F.

Melt the dark chocolate in a microwave-safe bowl by heating in 1-minute intervals, stirring between each interval until smooth. Let it cool slightly. This may take about 2 minutes total, depending on your microwave's power.

In a medium-sized mixing bowl, combine the dry ingredients: all-purpose flour, unsweetened cocoa powder, baking powder, and salt. Whisk them together until evenly blended, then set aside.

Using a stand mixer with a paddle attachment or a hand mixer, beat the softened butter, vegetable oil, and granulated sugar together on medium speed until the mixture becomes fluffy and pale.

Gradually add the whisked eggs, vanilla extract, and melted dark chocolate to the butter mixture, ensuring you scrape the sides of the bowl for even mixing.

Lower the mixer speed and carefully incorporate the dry ingredients into the wet mixture. Stir only until combined, avoiding over-mixing to maintain the brownies' tender texture.

Scoop approximately 1 ½ tablespoons of batter into each prepared cavity of the muffin tin using a small cookie scoop or spoon.

Bake for 12-15 minutes. To check for doneness, insert a toothpick into the center; if it comes out with moist crumbs, the brownies are ready. If it contains wet batter, bake a bit longer, checking every minute. The tops will deflate slightly as they cool, forming a signature crackly surface.

Let the brownie bites cool in the pan for about 10-15 minutes. Transfer them to a wire cooling rack to cool completely before adding the whipped topping. Store the cooled brownie bites in an airtight container in the refrigerator for up to one week.

For the best results, chill the mixing bowl and whisk attachment in the freezer for 10-15 minutes before preparing the whipped cream.

In the chilled bowl, combine heavy whipping cream, powdered sugar, unsweetened cocoa powder, and vanilla extract. Begin mixing on low speed to prevent the dry ingredients from scattering, then gradually increase to medium-high speed. Whisk until the mixture reaches soft peaks, about 2-3 minutes.

Add the mascarpone cheese to the whipped cream and continue whisking at medium-high speed until stiff peaks form, approximately 1-2 minutes.

Transfer the whipped cream mixture to a piping bag fitted with a decorative tip, such as a Wilton 8B. Pipe the whipped cream onto the tops of the cooled brownie bites. If you prefer, use an angled spatula to spread the whipped cream.

Garnish the brownie bites with chocolate curls or sprinkles for a finishing touch, if desired.