Soak porcini mushrooms (if using) for 30 minutes in hot water
Drain liquid and filter it through cloth or a paper coffee filter
remove grit. Finely chop the mushrooms.
In a large pot melt butter and gently saute onion, celery, carrot,
pancetta and bay leaf for 8 to 10 minutes.
Add ground beef, increase the heat slightly and cook until golden
Sprinkle in flour, stir through and cook for 30 seconds before
wine. Stir over a high heat until most of the wine has evaporated.
Add porcini mushrooms and their liquid and taste for salt before
seasoning. Add nutmeg and half the stock and simmer over a low
covered for 1 1/2 hours.
Stir from time to time and add remaining stock. When two-thirds
add milk and adjust seasonings. Just before serving stir in cream
chicken liver and cook, uncovered, for a final minute or two.
Note: Some like to add a tablespoon or two of tomato paste for
richness and color.
Recipe source: "The New Pasta Cookbook"