Bloom the yeast: Place 5 tablespoons of butter in a 4-cup measuring cup (affiliate link) and melt the butter in the microwave. Measure out 1/3 cup of sugar in a bowl. Add the milk and 2 teaspoons of sugar from the previously measured 1/3 cups.  Heat in the microwave for 30-40 seconds or until the milk reaches 105-110ºF. Sprinkle yeast over the top, stir to combine, let sit 15 minutes.

Make the dough: Meanwhile, in the bowl of your electric mixer (affiliate link)  fitted with the dough-hook attachment (affiliate link), add what's remaining of the 1/3 cup of sugar, 3 1/4 cup flour, potato flakes, and kosher salt. Turn the mixer on briefly to allow the ingredients to combine. With the mixer on low, slowly pour in the activated yeast mixture. Add the eggs, one at a time, waiting in between to allow the egg to mix in fully. When combined, increase speed to medium and run the mixer for 10 minutes. While the dough is mixing, drizzle a large bowl with a little oil and set aside. Remove the dough from the hook, if you still feel it's too sticky, add 2 tablespoons of flour, and knead it in the bowl a little. If the dough is still sticky and hard to work with, add the remaining 2 tablespoons. Shape dough into a ball using your hands and place it in the oiled bowl. Drizzle a little oil on the top, wrap with plastic wrap, and let the dough rise in a warm place for 1- 1 1/2 hours or until it doubles in size (see notes).

Make the swirls: Flour a flat surface and turn the dough out. Roll the dough out into a 9x24 inch piece. Spread the 2 tablespoons of softened butter on top. In a small bowl, combine the remaining 1/3 cup of sugar and cinnamon. Sprinkle evenly over the dough and if desired, sprinkle with raisins. Start rolling gently but firmly, using both hands. It's easier if you start at the far end and roll the dough towards you. Pinch the seams to contain the cinnamon sugar. Spray a 9x5 loaf pan (affiliate link) with a little cooking spray and gently lift the dough and place it, seam side down, in the prepared loaf pan. Cover with plastic wrap, let the dough rise for another 1 - 1 1/2 hours.

Bake: Position a rack in the center of the oven and preheat the oven to 350ºF. Melt the remaining 1 tablespoon of butter in the microwave and using a pastry brush, spread the butter on the dough. Bake the bread for 40-45 minutes or until the dough rises and browns on top. Mine took 43 minutes. Remove the bread from the pan and let cool before slicing and enjoying! Leftover bread makes amazing french toast.