Preheat oven to 350°F (177°C). Grease a 24-piece mini muffin pan and dust the inside of each well with cocoa powder or flour.
In a small bowl, whisk together the all-purpose flour, cocoa powder, and cornstarch until no lumps remain.
Place 2 to 3 inches of water into a large saucepan and bring to a boil. Reduce heat to medium-low.
In a large heatproof bowl, combine the finely chopped chocolate and espresso powder. Fit the bowl over the pot of just simmering water, making sure that the bottom of the bowl does not touch the water. Slowly melt the chocolate while occasionally stirring (see Chef’s Tips for more on this technique).
In a small, heavy-bottomed saucepan, place ⅓ cup (76 grams) of the cubed butter. Place saucepan over medium heat and stir continuously with a heatproof spatula until butter is melted, foam has subsided, milk solids in the bottom of the pot are golden brown, and butter has a nutty aroma; do not increase temperature to quicken the process or the milk solids may burn. Quickly remove from heat and stir in the remaining 2 tablespoons of butter (28 grams).
Remove the bowl of melted chocolate from the saucepan. Wipe any condensation from the bottom of the bowl. Add the Redpath® Dark Brown Sugar and sift the Redpath® Icing Sugar into the bowl of melted chocolate. Whisk until combined.
Whisk in the hot butter, scraping any browned bits from the bottom of the pot into the chocolate-sugar mixture, and thoroughly whisk until mixture is smooth. Add and whisk in the egg until fully incorporated. Add and completely whisk in the egg yolk until the mixture is smooth and glossy. Stir in the vanilla extract and salt.
Add in the dry ingredients. Using a large rubber spatula, fold in until the mixture is homogeneous. Fold in the chopped milk chocolate chips until evenly distributed throughout the batter.
Using a small trigger-style ice cream scoop or a tablespoon, scoop brownie mixture into the prepared pan, filling the wells ¾-full. Place the filled pan into the fridge to chill and allow ingredients to meld, sugars to dissolve, and the flour to hydrate; 15 minutes.
Place the chilled brownie bites into the preheated oven and bake for 10 to 13 minutes or until the tops are set, and a skewer inserted into the centre comes out with a few moist crumbs attached.
Allow brownies to cool in the pan before attempting to remove them; 10 to 15 minutes or until firm, but still warm. Run a small offset spatula around each brownie bite and carefully remove from the pan. Place the brownies onto a wire cooling rack to cool completely.
If desired, make one of the suggested buttercreams (Sweet and Simple Buttercream, Quick Buttercream or Swiss Buttercream) or icings (Royal Icing). Place into a piping bag fitted with a plain or star tip and decorate the completely cooled brownies (see “Simple Decorating Tips Using a Plain or Round Piping Tips” and “Simple Decorating Tips Using an Open or Closed Star Tip”) and sprinkle with nonpareils.
*Use any shape mini muffin or brownie tin; for example, heart-shaped brownies for Valentine’s Day are perfect for gifting to friends and loved ones. Ensure the wells are filled ¾-full. Adjust timing accordingly if using a bigger or smaller pan.
*Once the chocolate is 90% melted, turn off the heat and allow the residual heat to gently melt the remaining chocolate. Keep the bowl over the saucepan of water to keep chocolate warm while making the browned butter. The addition of the hot butter will melt any unmelted chocolate pieces.
*The browned butter in this recipe enhances the richness of the chocolate flavours and adds a subtle nutty flavour to these brownies.
*Due to the minimal amount of flour in this recipe, if the batter looks to be splitting (the fats not seeming to combine into the batter), it is fine to continue folding the batter until it all comes together.
*If milk chocolate chips are unavailable, use milk chocolate chunks or bars chopped into small, randomly sized pieces. Roughly chopping the chocolate chips is optional, though it creates a different textural mouthfeel and presentation than leaving them whole.
*Milk chocolate chips can be replaced with semisweet or dark chocolate for less sweet brownies.
*Redpath® Golden Yellow Sugar can be used in place of the Redpath® Dark Brown Sugar. Note that the brownies will have a more subtle undertone of caramel than if using the dark brown sugar.