Set up the barbecue grill for indirect cooking at a medium heat or around 350 degrees.
Drizzle peppers, onion, and garlic head with olive oil and sprinkle with salt.
Cook the peppers skin side down indirectly except to move briefly over the flame to char the skin.
At the same time, roast both the onion, head of garlic, and salsiccia on in-direct heat until golden and caramelized. +/- 30 min
Remove the cooked sausages, peppers, onion, and garlic head from the grill. Use a fork to remove the charred skin from the peppers.
Squeeze the cloves out of the head of garlic.
Roughly chop the peppers, onion, and garlic. Cut the Salsiccia sausages into slices.
Heat a cast iron skillet over the flame (or on the stovetop.) Melt the butter, add the flour, cook the roux for 1-2 min.
Deglaze with the white wine., scraping the bottom of the skillet to remove any browned bits, and wisking into the wine until well combined.
Add the cream, stock, salt, pepper, pepper flakes, red peppers, onion, garlic cloves.
Use an immersion blender (or traditional blender), to blend. The sauce does not need to be smooth. Check the salt ratio, you will need more and add as needed. Simmer for 2-3 minutes.
Serve with cooked pasta, sliced sausages, and garnish with lots of fresh basil, parmesan cheese, and cracked black pepper.