In the bowl of a stand mixer, whisk together the bread flour, sugar, salt, yeast, and spices/seeds. Using the dough hook, turn the mixer on low and slowly pour in the milk and melted butter. Increase speed to medium high and knead for 5 minutes.
Remove the dough hook and cover the bowl with plastic wrap. Place the bowl in a warm, draft-free area to proof (rise) for about 2 hours, or until doubled in size.
Refrigerate for at least 4 hours, but preferably overnight (the longer the dough is chilled, the easier it is to work with). Dough can be left in the refrigerator for up to one week.
On baking day, remove the dough from the refrigerator and dump onto a heavily flour surface. Knead gently until somewhat smooth. The dough is very sticky and loose, so use a bench scraper to help. Cut it in half with the bench scraper if you want to make two smaller loaves. You can also place half of the dough back in the fridge to bake fresh bread on another day.
Shape the dough into a torpedo shape and place it on a parchment-lined baking sheet or pizza peel (paddle). Cover with plastic wrap and place it in a warm, draft-free area to rise. It won't rise to double in size, just noticeably larger and puffy.
While the dough is rising, place a baking steel or baking stone on the middle rack of your oven and a shallow pan on the bottom rack. Preheat the oven to 450°.
When dough has fully risen, use the pizza peel (paddle) or the baking sheet and slide the dough onto the baking steel (or stone), parchment and all. Immediately pour one cup of very hot tap water into the shallow pan and close oven door. Bake for 30-35 minutes, or until the bread sounds hollow when tapped and is nicely risen. For a larger loaf (using all of the dough) add 5-10 minutes to the baking time. If the top is getting too dark before bread is done baking, cover lightly with aluminum foil.
Remove the bread from the oven and place on a wire rack. Allow to cool completely before slicing.