Method

• 01
  Preheat oven to 350 degrees F. Lighly butter and line an 8-by-8-inch square baking pan with parchment (the butter will keep the parchment from moving when you spread in the batter). Lightly butter parchment.
• 02
  In a small saucepan set over medium heat, melt butter. When it is completely melted and starts to sputter, add sugar and stir until smooth and paste-like. When it starts to sputter again, transfer it to a mixing bowl or the bowl of a stand mixer fitted with the paddle attachment. Mix on medium speed until mixture has cooled and no longer feels hot to the touch (it should read about 90 to 100 degrees on an instant-read thermometer).
• 03
  Add egg, egg yolk and vanilla; mix on medium-high speed for 2 to 3 minutes until pale yellow and falling off the beater in thick ribbons.
• 04
  Add flour, cocoa powder and salt and mix on low speed until dry ingredients just incorporated, scraping down the sides of the bowl and the beater to ensure everything is evenly mixed. Add milk and stir just until smooth.
• 05
  Dollops into prepared baking pan. Rather than dumping it all in the middle, it’ll be easier to spread the thick batter if you drop dollops of batter around the pan. Using a thin offset spatula, spread batter into an even layer.
• 06
  Bake for about 25 minutes or until a toothpick inserted in the center comes out with moist crumbs, but no raw batter. Depending on what kind of pan you use this time might be more or less (darker metal pans tend to cook more quickly, whereas glass pans can take much longer).
• 07
  Remove from oven and let cool slightly. If you notice the edges of your brownies are sticking up quite a bit, you can gently press with an offset spatula to flatten them out while the brownies are still hot (this will make the ganache go on in a smoother layer).
• 08
  To prepare ganache, place finely chopped chocolate in a heat-proof bowl. Warm cream in a small saucepan until it starts to steam and bubble (but be careful not to let it scald).
• 09
  Pour hot cream over chopped chocolate. Let sit for 30 seconds, then start whisking, gently in concentric circles starting in the middle. When you see a pocket of shiny chocolate in the center, that means you have created a good emulsion, start slowly whisking in wider and wider circles until all the cream is incorporated and the chocolate is fully melted. Add cubes of butter and slowly stir until smooth.
• 10
  Pour ganache over top of warm brownies, spreading into an even layer with an offset spatula if necessary. Scatter sprinkles over top.
• 11
  Let brownies sit at cool room temperature for 2 to 3 hours until completely set. You can refrigerate them if you’re in a hurry, however the ganache will lose its shiny finish. A wine fridge is also a great way to set the ganache without losing the shine.
• 12
  Lift brownies out of pan using parchment as handles. Cut into 16 squares (or bigger/smaller as desired). Brownies will keep at cool room temperature in an airtight container for 2 days, or in the refrigerator for up to 7.