Sicilian Pistachio Sauce with fresh Pasta

Back to the Island of Sicily and back to a dish I ate there.
Farmers grow lots of pistachio and almond trees here and the pistachios are famous for their taste.

One evening we had as a first coarse a bit of homemade pasta in a creamy sauce. It was not green, but it had a lovely bite to eat. That it was nuts- or pistachios took a moment to comprehend. Not that the pistachio taste was dominant, but it left a great mouthfeel.

Our guide told us how the sauce was prepared. I thought it was a roux with butter, onions and some flour and then added pistachios, but I was wrong- but only a bit.
Sicilians use a flour for the roux, but it is pistachio flour and they add tiny bits of pistachios later as a finish.

recipe for 2:
300 g fresh tagliatelle pasta
2 tbsp pistachios
1 tbsp butter
3 spring onions
1 clove of garlic
1 tbsp double cream
salt and pepper
1 tbsp parsley

Sauté the onions and garlic (fine diced) in butter until they are very soft.
In a kitchen blender ground 1 tbsp of pistachios to a finer crumb/flour.
Add that to the onions and make kind of a roux..
Cook the pasta in salted boiling water.
Use some of the pasta water to loosen the "roux"

When you drain the fresh pasta, keep lots of pasta water for the sauce.

Add the cream and the pasta and loosen with more water.
Add the tbsp of chopped pistachios. Season  with pepper and a bit of salt. Finish with parsley.