• Remove the skin, finely crumble the sausage with your hands, and set aside.
• Remove the skin, finely chop the onion, and set aside.
• In a pot, gently melt the butter in the olive oil, add the onion and a pinch of salt, and sauté on a medium stove and low flame for 8 minutes.
• Add the sausage and sauté on low flame for about 10 minutes, stirring occasionally. Use the wooden spoon to make the sausage pieces even smaller; its grain should be fine.
• Turn up the stove flame, add the wine, and let it evaporate for a few minutes while stirring.
• Then turn the heat down, add milk, tomato paste, and stir.
• Cover the pan with a lid, not completely, and cook slowly and long, about an hour and a half, stirring occasionally and adding broth during cooking. The sauce has to be reduced but not dry.
• Taste, adjusting the salt if needed.

Food tips

• If the sausage still seems too coarse, at the end of the cooking, use the immersion blender to pulse here and there for a moment and stop.
• Store in the refrigerator for up to a week or in the freezer for up to a month.