I am currently on a holiday in Baleal, Portugal near the big fishing port of Peniche. The other day I went into the supermarket and saw a sort of chouriço that I have never previously seen before.
It had a very dark colour but looked quite different to the local black pudding or mocela though I wondered if blood was an ingredient. The name means literally chorizo of onion. It was not cheap but I thought it was worth a try.
We tried it sliced and there was a very pleasant foretaste of onion but a less pleasant blood aftertaste. While I do not speak Portuguese I looked at the ingredients and there is 'sangue' which doubtless means blood.
The second time I lightly grilled the slices and the taste was very pleasing. The taste was somewhere between conventional chouriço and black pudding. This might go well in a salad with thinly sliced bacon.
We later tried the chouriço de cebola grilled for just 5 minutes (shown above with the conventional version) and the taste was much improved in our view. There is no guarantee that this is the authentic way to eat it!
Shipscook
You could try it sliced with canelli beans and a tomato sauce, it would be just like that Spanish breakfast where you have chorizo and black pudding only with just the one sausage.
I posted a recipe for something similar earlier this year called I think a Hispano-Irish breakfast as I could not get a Spanish Black pudding and had used one of those really nice Irish Galte Black Puds