Melt butter in heavy medium skillet over medium heat. Add onion and saut&é until soft and translucent but not brown, about 8 minutes.
03Combine ground pork and chopped bacon in large bowl. Using fork or fingertips, mix together until well blended.
04Add sautéed onion, garlic, 2½ teaspoons salt, thyme, allspice, and pepper to bowl with pork mixture and stir until incorporated. Add eggs, cream, and reduced Cognac. Stir until well blended.
05Line 9x5x3-inch metal loaf pan with bacon slices, arranging 8 slices across width of pan and 3 slices on each short side of pan and overlapping pan on all sides. Using hands, lightly and evenly press half of meat mixture (about 3¼ cups) onto bottom of pan atop bacon slices. Arrange ham strips over in single layer. Top with remaining meat mixture.
06Fold bacon slices over, covering pâté. Cover pan tightly with foil. Place pan in 13x9x2-inch metal baking pan and transfer to oven. Pour boiling water into baking pan to come halfway up sides of loaf pan. Bake pâté until a thermometer inserted through foil into center registers 155°F, about 2 hours 15 minutes.
07Remove loaf pan from baking pan and transfer to rimmed baking sheet. Place heavy skillet or 2 to 3 heavy cans atop pâté to weigh down. Chill overnight. Do Ahead Can be made 4 days ahead.
08Place loaf pan with pâté in larger pan of hot water for about 3 minutes. Invert pâté onto platter; discard fat from platter and wipe clean. Cut pâté crosswise into ½-inch slices.