I must note that I don't own a pasta machine (one of many things on my "to buy" list when one day I finally have a bigger kitchen), and you can certainly do this without a pasta machine, but it just means you need to roll the dough even and thin enough.
100g dark, pure cocoa (no sugar added)
25g caster sugar
pinch of cinnamon*
1/2 tsp vanilla extract
pistachios, to serve
*I had to fight the temptation to add some matcha in the dough...
Sift together flour and cocoa. Add sugar and cinnamon and mix well. Make a well in the centre of the flour and crack the eggs into the centre of the well. Add vanilla in the mix. Using a fork gradually whisk in the eggs until the dough becomes thick. Knead the dough until smooth and elastic. Roll the dough into a thin sheet and cut the sheet into long, 1cm wide strips. Boil water in a large saucepan, add the tagliatelle and cook for 3 minutes. Drain well. You can serve this with chocolate sauce, nuts, cream, ice cream...the choice is yours :-)
Serve with pistachios