Heat 1 tbsp of olive oil over medium high heat and add half the ground meat. Brown it without breaking it up too much. Set aside and repeat with the other half.

Heat the remaining 1 tbsp of olive oil in a heavy saucepan over medium heat and fry the pancetta until browned. Remove pancetta, leaving fat in the pan.

Add onions, celery, carrot, and a pinch of salt and pepper to the pan; fry until soft, about 10 minutes. Add garlic and herbs, and cook for another 5 minutes.

Add the ground meat and pancetta back to the pan, mixing in the tomato paste. Cook for 5 minutes, breaking up the meat well.

Add the wine and reduce for 8 - 10 minutes. Add stock and milk; bring to a simmer. Season as necessary, then lower the heat and cook uncovered for 3 - 4 hours, stirring occasionally.

Add lemon juice, salt, and pepper to taste. Let cool to room temperature before refrigerating.

For the pasta, combine '00' flour and semola flour, add eggs, and knead into dough. Divide and roll out into sheets. Blanch in salted boiling water for 30 seconds, then cool and pat dry.

For the béchamel, melt butter, and whisk in flour to form a paste. Gradually add milk, whisking until thickened. Stir in 100 g parmesan, salt, and pepper; set aside.

Preheat oven to 190 degrees C (375 F). Lightly grease lasagne pan with butter.

Layer the assembled lasagne: spread 1 cup bolognese on the bottom, add ½ cup béchamel, two sheets of pasta, and continue layering with remaining bolognese, béchamel, and parmesan. Finish with a final layer of bolognese and 1 cup béchamel topped with remaining parmesan.

Cover with foil and bake for 20 minutes. Remove foil and bake for an additional 30 minutes or until bubbly and golden.

Let firm up for 15 - 20 minutes before serving.