Bolognese Sauce

This is the old standard, the familiar meat and tomato sauce served in its thousands of variations
over spaghetti in homes, diners, and fine restaurants everywhere.  The addition and reduction
of stock and wine greatly enrich and intensify the flavor of this more traditional version of
bolognese sauce.  There is another optional flavor intensifier, as you will see.

Ingredients:
One large onion, chopped
One celery stalk, chopped
One carrot, grated or chopped fine
One 28 ounce (850 ml) can of crushed tomatoes with tomato puree
One quarter cup (30 ml) chopped fresh parsley
One quarter teaspoon (1 ml) freshly ground black pepper
Two cups (500 ml) chicken or beef stock, beef preferred
Two cloves garlic
One pound (500 g) very lean ground beef
One and one half (350 ml) cups dry red wine
Optional: one quarter pound (100 g) chicken livers, trimmed of sinew and minced fine
(The chicken livers will add great depth of flavor to the finished sauce.  The sauce
will not taste like liver.  If you don't tell, nobody will know why the sauce is so delicious.)

Method:
In a large skillet, warm 3 tablespoons (50 ml) olive oil then add the onion, celery and carrot.   Stir to coat
the vegetables with oil and cover the pan.  While the vegetables are cooking, place the crushed tomatoes
in a crock pot turn to high heat.  Add the parsley and and pepper and stir in.  Put the lid on the crock pot.
When the vegetables are limp, turn the heat under the skillet all the way up and add the beef or chicken
stock and reduce until almost dry, stirring to prevent scorching.  When the last of the stock is almost
evaporated add the crushed garlic cloves.  When the reduction is complete and the vegetables are starting
to caramelize but before they scorch add this reduction to the crock pot.
Using the same skillet, brown the ground beef and the minced chicken livers, breaking up into fine bits as it
cooks.  When browned, add the wine and reduce until the liquid is gone, again being careful not to scorch
the reduction.  Add the meat to the crock pot.  When all is bubbling well reduce the heat to low.
Simmer for several hours.  You will probably want to leave the cover off during some of this cooking time
to further reduce the sauce.  It should be thick, not soupy.
Serve over pasta of choice (tagliatelle is traditional but use whatever pasta you like), topping with a grating
of Parmesan cheese.