In a stand mixer fitted with the paddle attachment or a large mixing bowl, combine 1 and 1/2 cups flour, yeast, sugar, and salt.
In a small saucepan over medium, heat the buttermilk, water, and shortening until very warm (120 to 130 degrees F) but not hot (the shortening does not need to melt). Pour all at once into the flour mixture, add eggs, then blend at low speed just until moistened. Increase speed to medium and beat for 3 minutes. On very low speed (or by hand with a wooden spoon) gradually stir 1 and 1/2 cups of the remaining flour. Stir in the remaining 1/2 cup flour a few tablespoons at a time, only adding enough to make a firm dough. It will feel tacky, but should not be excessively sticky.
Switch to a dough hook (if using a stand mixer) or turn out on a lightly floured surface. Knead until smooth and elastic (6-8 minutes by hand or 4-6 minutes by machine). Place the dough into a lightly oiled bowl and turn the dough to coat (this prevents a crust from forming). Cover and let rise in a warm, draft-free place until the dough nearly doubles in size. To test the dough, gently press it with two fingers. If your indent remains, the dough is ready.
Prepare Filling: In a small bowl, combine the honey, nuts, raisins, orange juice concentrate, and cinnamon. Set aside.
Gently punch the dough down, then divided into 2 equal parts. Turn the first half out onto a lightly floured surface and roll it into a 12-inch square. Spread the square with half of the softened butter, then top with half of the filling, leaving 1 inch of space uncovered at the edge that is farthest away from you. (The filling will spread to fill this space as you roll the dough). Starting with the edge nearest to you, roll the dough up tightly, then pinch the edge to seal. Cut roll into 12, 1-inch slices. Generously grease a 10 or 12-cup bundt or tube pan. Lay the slices horizontally in the pan in 2 layers as follows: Place 6 slices per layer and alternate position of slices in each layer. Repeat with second half of dough, continuing to alternate the slices so that you have 4 layers total.
Cover pan loosly with plastic wrap and let rise in warm place until indentation remains after lightly touching the rolls, about 45 minutes to 1 hour. (Alternatively, you can place the pan in the refrigerator to rise overnight, then bring to room temperature prior to baking).
Preheat oven to 350 degrees F. Bake rolls for 20 minutes, remove from oven and cover with aluminum foil, then return to oven to bake 15-20 additional minutes, until the rolls are light golden brown. Invert immediately onto a cooling rack.
Prepare glaze: In a small bowl, combine powdered sugar, butter, and 1 tablespoon milk. Blend until smooth, adding additional milk as needed until your desired consistency is reached. Drizzle over cake and serve warm.
Make-Ahead. After Step 6, place the pan in the refrigerator overnight, then bring to room temperature prior to baking.
To Store. The coffee cake will keep at room temperature, covered tightly with plastic for up to 4 days
To Freeze. Wrap tightly in plastic and freeze for up to 1 month. Defrost overnight in the refrigerator before serving.