Slowly cook pancetta in skillet 6-10 minutes or until crisp; drain on paper towels. Reserving 1 tablespoon of drippings in skillet, add rendered duck fat and saute onion medium-high heat 5 minutes, until almost tender. Deglaze with sherry and 1/3 cup of chicken stock until reduced almost completely.

In your favorite soup pot, mix onion, stock and potatoes. Heat to boiling; reduce heat. Cook 10 minutes or until potatoes are very tender.

Meanwhile, in same skillet, melt butter over low heat. Stir in flour with whisk until smooth. Cook and stir 1 minute. Gradually stir in milk. Pour milk mixture into potato mixture. Add half and half, the salt and pepper. Cook over medium heat, stirring constantly with whisk, until mixture is thickened and bubbly.

Stir in half the pancetta, the creama mexicana, 1 cups of the cheese and 1/2 cup of the green onions.

Cook until thoroughly heated and cheese is melted.

Evenly top individual servings with remaining pancetta, the rest of the Manchengo and green onion.