In a large mixing bowl, whisk together 3 cups of all-purpose flour, the packet of instant yeast, granulated sugar, and salt. Set aside.
In a small saucepan, combine the milk, water, and 3 tablespoons of unsalted butter. Heat over low heat until warm to the touch (about 110°F or 43°C). Remove from heat.
Pour the warm milk mixture into the dry ingredients. Add the Idahoan potato flakes and the large egg. Mix until the dough starts to come together.
Turn the dough out onto a floured surface and knead for about 5-7 minutes until it becomes smooth and elastic. If the dough is too sticky, add a little more flour, a tablespoon at a time.
Place the kneaded dough in a greased bowl, cover with a kitchen towel, and let it rise in a warm place until doubled in size, about 1 hour.
After the dough has risen, punch it down and turn it out onto a floured surface. Roll it into a large circle about 1/4 inch thick. Cut the dough into 8 equal wedges.
Starting from the wide end of each wedge, roll the dough towards the point to form a crescent shape. Place the rolled crescents on a baking sheet lined with parchment paper.
Cover the crescent rolls with a kitchen towel and let them rise again for about 30-45 minutes until puffy.
While the rolls are rising, preheat your oven to 375°F (190°C).
Once the rolls have risen, brush the tops with the melted butter. Bake in the preheated oven for 15-20 minutes, or until golden brown.
Remove the rolls from the oven and let them cool slightly on a wire rack. Serve warm, and enjoy every flaky bite!