For the Lamb Ragù:

In a saucepan over medium flame, heat oil. Add American lamb and cook until browned.
Using a slotted spoon, remove lamb and transfer to a nonreactive container. Set aside.
In the same pan, add onions, carrots, celery, and garlic. Reduce heat and cook 1 hour, or until vegetables are softened and alliums are caramelized.
In a Vitamix Commercial blender, purée tomatoes until smooth. Strain and set aside. Add spices to pan and stir to incorporate. Cook 2 minutes. Deglaze pan with wine and cook until alcohol has dissipated. Stir in tomato purée, milk, and herbs.
Cook 2 hours, adding water to thin, if needed. Remove and discard bay leaves. Stir in reserved lamb. Season with salt. Transfer to an airtight container and refrigerate.

For the Dough:

In a large mixing bowl, add all ingredients and mix until dough comes together. Transfer to a lightly floured work surface and knead 5 minutes, or until dough is smooth and elastic.
Wrap in plastic wrap and let sit 1 hour at room temperature.

For the Tagliatelle:

Using a sheeter, roll out Dough until 1 1/2-millimeters-thick. On a lightly floured work surface, cut dough lengthwise into 30-centimeter-long strips. Lightly coat with semolina flour. Transfer to an airtight container and refrigerate.

To Assemble and Serve:
In a pot over medium-high heat, bring water to a boil. Season heavily with salt and add 115 grams Tagliatelle.
Cook 1 minute, reserving pasta water.
In a sauté pan over low heat, add Parmigiano Reggiano and 120 grams Lamb Ragù.
Using tongs, transfer cooked Tagliatelle to pan. Add a splash of pasta water. Increase heat and sauté 20 seconds, or until sauce is fully emulsified.
Transfer mixture to a serving bowl. Finish with Pecorino Romano.