• Heat milk, vegetable oil, and ½ cup sugar in a medium saucepan over medium heat. Let the mixture get really hot, but remove from heat right before it comes to a boil. Pour milk mixture into a large bowl and let cool to lukewarm.
• Sprinkle yeast over milk mixture and let sit for about 1 minute.
• Add 4 cups of the flour to the bowl and stir until just combined.
• Cover bowl with a clean kitchen towel and set aside in a relatively warm place to rise for an hour.
• Remove towel and add 2 Tbsp cinnamon, baking powder, baking soda, salt and remaining ½ cup of flour and stir thoroughly to combine.
• Place dough on a lightly floured surface and roll it into a large rectangle, about 30×10 inches.
• Melt butter in a small saucepan over medium heat and pour 1 Tbsp of the melted butter into each of two round baking dishes or pie plates (you can also use disposable foil cake pans).
• Pour remaining 6 Tbsp melted butter over the surface of the dough and use a pastry brush (or your fingers) to spread the butter evenly. Generously sprinkle brown sugar and remaining 2 Tbsp cinnamon over the butter and top with diced apples and walnuts.
• Starting at the long end farthest from you, roll the dough tightly toward you using both hands to roll evenly. Pinch the seams together at ends. Transfer dough to a cutting board and using a sharp knife, cut dough into roughly 1 ½-inch slices.
• Place rolls into preparing pans, taking care not to over-crowd the pans. Cover the pans with a kitchen towel for about 20 minutes, so they can rise again. While they're rising, preheat oven to 375 degrees.
• Bake rolls for 18-22 minutes, until they're turning golden around the edges. Remove from oven and immediately pour icing over them.

Cinnamon Roll Icing

• In a medium bowl, whisk all the ingredients together until smooth.