Preheat the oven to 350°F/175°C and line and grease a 9×9 inch baking pan.
In a bowl, add the hot butter and chocolate chips. Whisk together until the chocolate has melted and it's well combined.
1/2 cup butter, 3/4 cups semi-sweet chocolate chips
Add in the sugar and continue on whisking.
1/2 cup white sugar
Into a separate bowl whisk the two eggs with a fork until light air bubbles form on the top. This takes about 30 seconds.
2 eggs
Add the eggs, vanilla, and coffee into the bowl and whisk together.
2 eggs, 2 tsp vanilla, 2 tsp instant coffee
Toss in the sifted flour, baking powder and salt and fold using a spatula until just combined. The batter will be runny.
1/3 cup flour, 3/4 tsps baking powder, 1/4 tsp salt
Pour half the batter into your prepared pan and spread it so it covers the entire bottom. Add 5 of the Kinder Bueno chocolate bars on top. Then add remaining batter and spread evenly. The Kinder Bueno shouldn't be showing. Scroll up and check out the reference photos for details.
8 Kinder Bueno Chocolate
Bake for 22-26 minutes or until a toothpick comes out crumbly. Start checking around the 18 minute mark.
Let cool in oven for 5 minutes with the oven door slightly cracked. Then remove and top off with additional Bueno pieces (optional). The brownies will be very fudgy. Cool in pan completely, then cut into squares and enjoy!