In the bowl of a stand mixer, combine water, yeast and 1 tsp sugar. Whisk to combine and let sit 5 minutes, or until yeast mixture is foamy. Add to it milk, butter, remaining sugar, egg yolks, orange zest, salt and 3 cups flour. Mix on low speed with paddle attachment until just combined. Switch paddle attachment with dough hook and increase speed slightly, add the remaining 1 cup flour in increments. Once all flour has been added, increase speed to medium and knead about 5 minutes, or until dough is slightly sticky, smooth and elastic (add a little bit more flour if it's really tacky until it's at the right consistency). Remove dough from bowl and place in a large lightly greased bowl, cover it with plastic wrap and let rise until doubled, about 1 to 2 hours.

Once dough has risen, punch down and place on a lightly floured countertop and let rise 20 minutes.

In the meantime, make the filling -- combine brown sugar and cinnamon in a bowl. Melt butter and keep separate.

Roll out dough into a 12-by-18-inch rectangle. Brush with melted butter and sprinkle with brown sugar/cinnamon mixture. Sprinkle with orange zest. Starting from the long side, roll up dough into a tight cylinder. Place seam side-down on a flat surface and cut crosswise into 15 equal slices.

Make the topping -- in a small saucepan, combine butter, brown sugar, honey, orange juice and orange zest over low heat. Stir until butter and sugar are melted. Pour mixture into a greased 9-by-13-inch pan and sprinkle pecan halves on top.

Place dough slices flat side-down on top of prepared topping, crowding them so they touch. Cover loosely with plastic wrap and place in refrigerator overnight to rise. In the morning, preheat oven to 375 degrees F -- remove buns from the refrigerator and let stand on countertop while oven preheats. Bake buns until golden brown, about 30 minutes; immediately invert pan onto a baking sheet or serving tray. Let buns cool slightly and serve warm.