Arrange the oven rack in the center and preheat the oven to 350 Fahrenheit.
In a microwave-safe bowl add the butter and the dark chocolate chunks. Melt them in 20 second intervals, mixing in between each cycle. It took about 1 minute to melt the chocolate. Let it cool down for about 5 minutes.
200 grams unsalted butter, 100 grams Dark chocolate chunks
In a bowl, with a hand mixer on medium speed, beat the eggs and sugar until they become frothy and double in size, about 2-3 minutes.
3 eggs, ¾ cup white sugar
Add the chocolate mix to the egg and sugar mix, add vanilla extract, the Milo and flour and mix with a spatula, we don't want to add a lot of air to the mix.
2 cups Milo, 1 teaspoon vanilla extract
Add the chocolate chips and chocolate chunks.
¼ cup Semisweet chocolate chips, ¼ cup Milk chocolate chips, ¼ cup Milk chocolate chunks
Line a 9x7 baking dish with 2 sheets parchment paper, crossing one over the other. Press sides into the corners. Use small metal clamps to keep the parchment paper in place if needed.
Lightly spray the parchment paper with baking spray or a neutral oil.
Scrape the batter into the prepared baking dish and spread evenly.
Bake the brownies until the surface is shiny for about 25-30 minutes.
Remove the brownies from the baking dish and cool them for about 15 minutes before cutting.
Slice the brownies into 12 squares