How to Make It
On a sheet of wax paper, mix 2 tablespoons of the ground gingersnaps with the flour. Cut the pork tenderloins crosswise, about 2 inches thick. Gently pound each piece to a 1-inch thickness. Season the pork with salt and pepper and dredge in the flour mixture.
In a large skillet, melt 1 tablespoon of the butter in the olive oil. Add the pork all at once and cook over moderately high heat, turning once, until browned and nearly cooked through, about 6 minutes. Transfer the pork to a plate.
Add the shallot to the skillet and cook over moderate heat until softened, about 1 minute. Add the Calvados and cook, stirring, until reduced by half, 1 to 2 minutes. Add the chicken broth and apple cider and simmer until reduced to 1 cup, scraping up any browned bits from the bottom of the pan, 5 minutes. Add the vinegar and the remaining 2 tablespoons of ground gingersnaps and 1 tablespoon of butter and cook, stirring, until thickened, 1 minute. Return the pork to the skillet and cook for 1 minute longer. Transfer the pork to plates and spoon the sauce on top. Garnish with the crushed gingersnaps and chives.