Step 1
For the pasta dough: Steam the spinach in a steamer or over boiling water until bright green 2 minutes. Squeeze to remove excess moisture and process in a food processor to make a paste. Combine spinach with eggs semolina and salt and process until smooth. Stir in enough of the flour to make a smooth dough. Knead briefly cover and set aside.
Step 2
For the ragu: In a large skillet melt butter over medium-high heat. Saute bacon carrot celery and onion until onion is translucent. Stir in ground pork ground beef and minced ham and cook until browned. Stir in tomato paste oregano and beef stock. (Reserve the chicken livers for later.) Season with salt and pepper reduce heat to low cover and simmer 20 minutes.
Step 3
For the bechamel: While the ragu is simmering combine 2 tablespoons butter and 2 tablespoons flour in a medium saucepan over medium-low heat. Whisk to make a roux. Remove from heat let rest one minute then whisk in warm milk. Return to heat simmer 10 minutes stirring constantly until thickened. Season with salt and nutmeg. Remove from heat.
Step 4
To cook pasta: Bring a large pot of lightly salted water to a boil. On a floured surface divide pasta dough into three portions. Roll each portion out to a thin sheet. Have ready an ice water bath. Cook each sheet 3 minutes in the boiling water; remove from the boiling water and dip in the ice water; drain and dry on a clean dry cloth.
Step 5
To finish the ragu: Stir the chicken livers into the simmering sauce. Cook 1 minute remove from heat and set aside.
Step 6
Preheat oven to 400 degrees F (200 degrees C). Grease a 9x13 baking dish.
Step 7
To assemble lasagna: Place one pasta sheet in bottom of prepared baking dish. Spread one-third of the ragu one-quarter of the bechamel one-third of the ricotta and one-quarter of the parmesan over the pasta. Repeat layers twice. Top with remaining bechamel and parmesan and dot with butter.
Step 8
Bake in preheated oven 30 minutes until top is golden brown.