How to Make It
Whisk together stock, yeast, and 1 tablespoon of the honey in the bowl of a heavy-duty electric stand mixer fitted with dough hook. Let stand 5 minutes. Add all-purpose flour, bread flour, thyme, sage, salt, pepper, 5 of the eggs, and remaining 2 Tbsp. honey. Beat on low speed until just combined, 2 to 3 minutes, stopping to scrape bowl as necessary. Continue to beat on low speed until dough is well combined but still very tacky, 3 to 4 minutes. With mixer running on low speed, add duck fat, 2 tablespoons at a time, beating just until blended after each addition. Stop mixer occasionally to scrape down bowl. Increase speed to medium, and beat until dough is elastic and soft, 15 more minutes. Increase speed to medium-high, and beat until dough has formed a ball and comes away from bowl cleanly, about 1 more minute. Place dough in a large bowl coated with cooking spray. Loosely cover with plastic wrap, and let rise in a warm place (80°F to 85°F), free from drafts, until doubled in size, 1 1/2 to 2 hours.
Coat 2 (9- x 5-inch) loaf pans with cooking spray. Very gently divide dough in half, and pat each into a 9-inch square on a lightly floured surface, being carefully not to pop too many bubbles. Gently fold each square into thirds (like a letter). Lightly press seam to seal. Place each folded dough square, seam side down, in a prepared baking pan. Loosely cover with plastic wrap, and chill 6 hours or overnight. Remove from refrigerator, and let stand at room temperature until dough is soft and cresting above edges, about 1 hour.
Preheat oven to 350°F with 1 rack in upper third and 1 rack in lower third of oven. Place an ovenproof skillet on bottom rack. (Do not remove skillet while oven preheats.)
Whisk remaining 1 egg. Gently brush loaves with whisked egg. Add hot water to preheated skillet on bottom oven rack. Place loaf pans on rack above skillet. Bake loaves until tops are golden brown and a thermometer inserted in thickest portion registers 190°F, 35 to 45 minutes. (Cover loosely with aluminum foil to prevent excess browning, if necessary.) Cool in pans on a wire racks 30 minutes. Remove from pans, and cool completely, 30 to 45 minutes. Cut each loaf into 10 slices.