Preheat the oven to 200 degrees F. Spread out the pretzel cubes on baking sheets and bake, flipping cubes halfway through, until the bread dries out, about 1 hour. Set aside to cool and increase the oven temperature to 375 degrees F.
Fry the bacon until crisp in a large saute pan. Remove to a paper towel-lined plate to cool. Drain off 1/4 cup bacon grease from pan; set aside. Add the onion and celery to the pan with the remaining bacon grease and cook over medium heat until soft, about 5 minutes; season with salt and pepper. Set aside.
Whisk together the chicken broth, beer, mustard, honey and eggs in a medium bowl.
Grease a 9-by-13-inch casserole dish, then gently combine the bread cubes, bacon, parsley and onion/celery mixture in the dish. Pour the broth mixture over the top and toss gently to coat. Pour the reserved bacon grease over the top; bake until set and golden, about 40 minutes.