Preheat oven to 180 Degrees Celcius or 350°F (180°C). Line roasting tray with baking paper. A tray approx 30 cm x 20cm is ideal, although a variance in tray size will just make a taller or thinner slice so it's not that important.
Add the chocolate to the TM bowl. Mill 3 sec/Speed 9.
Add the butter, sugar and vanilla extract to milled chocolate in the TM bowl. Melt 5 min/100 degree/Speed 3.
Add eggs to TM bowl. Combine 20 sec/Speed 4.
Scrape down the bowl and add flour, cocoa, baking powder and salt. Mix 1 min/Speed 4.
Pour the batter into the pan and spread evenly. Bake for 18-20 minutes, or until cooked
Remove the fudge base from the oven and allow to cool in the tray.
Nutella Fudge
Add sweetened condensed milk, butter, chocolate melts and Nutella to the TM bowl. Melt 5min/100 degrees/Speed 2.
Scrape down the bowl and if the mixture isn't completely smooth repeat. 1 min/100degrees/Speed 2.
Spread the Nutella Fudge over the chocolate Brownie base, the base does not need to be cooled prior to the fudge being added to the top.
Notes
Refrigerate the slice prior to cutting. Store in the fridge until serving.The nutritional information is based 30 pieces, you could easily reduce the calories by reducing the size of the slice.