Sweat shallots with butter, add tomato paste, Chablis, and reduce by ½ medium high heat.
Add crème fraiche and heavy cream and cook for 10 min hard simmer.
To finish sauce:
To make Beurre Manie, use your fingertips or wooden spoon to knead together equal parts by weight, softened butter and flour. Can be made in larger batches and reserved for use as needed.
Bring sauce to a boil. Mount sauce with butter and whisk in beurre manie to thicken the sauce. Strain sauce and reserve.
For the dish:
Cook the tagliatelle pasta until al dente. Strain water and return to saucepan.
Add the jambon madrange and chablisienne sauce into the pan of cooked pasta and simmer until heated through.