Season the chicken with salt and freshly ground pepper.

In a large, heavy bottomed sauté pan, melt 2 T. of the butter over med-high heat. Brown the chicken breasts and then turn. Sprinkle with half of the tarragon and all of the shallots. Cover and cook over low heat 15 minutes.

Remove the cover and sprinkle with the wine. Cover and cook 10 – 15 minutes more. Transfer the chicken and wine to a bowl and keep warm while making the sauce.

Add remaining butter to the pan. Melt over med-high heat and add the flour. Lower the heat and cook 2 minutes. Add the evaporated milk and whisk to smooth, bring to a simmer and cook 5 minutes. (Once the milk is added, never bring to a full boil or it will curdle) Add the calvados and return chicken and wine to the pan and add the remaining tarragon.

Spoon the sauce over the chicken and serve immediately on a hot platter.