Boudin noir in English is "blood sausage" or (mostly British) "black pudding". The English word "pudding" is a derivative of the French word boudin. For boudin noir, the filling inside the sausage casings is a kind of pudding. There are also boudins blancs, which are made with a "pudding" of bread crumbs, pureed chicken, turkey, or pork, with herbs, mushrooms, truffles, etc.
Here are the ingrédients as listed on the packaging of the boudin noir that we ate, and which I bought at SuperU.
• sang de porc 36,5% (origine France) [blood]
• oignons 34% [onion]
• gras de porc (origine France) [fat]
• couenne (origine France) [pork rind]
• sel, sucre, épices et plantes aromatiques [salt, sugar, spices, herbs]
• boyau naturel de porc [casings, a.k.a. pork intestine]
Remember, natural sausages are made using pork intestines as casings (including hot dogs). Or the intestines of other animals like lambs. And all the meat we eat contains blood, to one degree or another. So boudins noirs are good eats. And tasty. Especially when served with good, hot Dijon mustard.
This is a savory apple tart made with boudin noir. Apples and pork are a good marriage. Here's a link to the recipe.
Boudin noir is sold already cooked. It's good warmed up in a frying pan on medium heat, in a hot oven, on a barbecue grill, or even in the microwave for 5 minutes at about 450 watts (medium). Or baked in a tart.