To prepare the brownies:

1. Preheat the oven to 350 degrees. Line one quarter sheet pan (or one 9”x13” pans) with foil that extends up the sides and grease with baking spray. Set aside.
2. In a small saucepan over low heat, gently heat the chocolate and butter, stirring regularly, just until barely melted. Pour the mixture into a large bowl and whisk in the sugar and brown sugar. Whisk in the eggs and the vanilla extract. Scrape the sides of the bowl and then fold in the flour, cocoa powder, and salt. Spread the batter evenly in the pan and bake in the preheated oven for about 15-17 minutes or until a toothpick inserted only comes out with a few moist crumbs. Set aside to cool completely.
3. When ready to prepare your petit fours, place the chocolate in a heat-safe bowl. Gently warm the cream in the microwave or on the stovetop until it is almost ready to begin bubbling. Pour the warm cream over the chocolate and whisk to combine until smooth. Gently heat in the microwave in 15 second increments until melted as needed.
4. If you wish to make the tiny bite-sized chocolate-coated petit fours, use a tiny biscuit cutter or sturdy round cutter about 1 to 1-1/4” in size to trim out rounds from your cooled brownies. I prefer to freeze the brownies for about an hour prior to cutting to make the cutting easier. For larger stacked petit fours, use a 1-3/4 to 2” cutter to trim out rounds.
5. For the tiny petit fours, place the small brownies on a cookie sheet set over a large bowl and spoon the warm liquid ganache over top. Use a fork to transfer the covered petit fours onto a baking sheet lined with wax or parchment paper. Allow to set up slightly before sprinkling with a bit of fleur de sel.
6. For the large stacked petit fours, allow the ganache to set up slightly either on the counter or in the fridge until it turns into a slightly thickened but still pipeable fudgy consistency. Place the mixture into a piping bag fitted with a round tip and squeeze dollops into the center of each brownie round. Top one brownie with another and sprinkle the tops of each stack with sea salt, sprinkles, or whatever! Enjoy at room temperature!