Step 1

Stir together water and yeast in bowl of a stand mixer fitted with a dough hook attachment, or in a large bowl. Let stand at room temperature until yeast is foamy, 5 to 10 minutes.

Step 2

Cut ¼ cup butter into 6 pieces. Add flour, instant potatoes, sugar, egg, kosher salt, onion powder, garlic powder, and butter pieces to yeast mixture. Beat on medium-low until smooth and elastic, 6 to 8 minutes. Alternatively, mix by hand with a sturdy spoon until a rough dough forms. Transfer to a lightly floured work surface; knead until smooth and elastic, 6 to 8 minutes.

Step 3

Shape dough into a smooth ball. Place in a large bowl lightly greased with cooking spray, turning to coat on all sides. Cover tightly with plastic wrap or a bowl cover. Let stand in a warm place (75°F to 80°F) until dough doubles in size, 1 to 1½ hours.

Step 4

Lightly grease a 10-cup Bundt pan with cooking spray. Melt remaining ¼ cup butter. Divide dough into 16 equal pieces; shape into balls, flouring hands lightly if needed. Place 8 balls in base of pan. Drizzle with 1 tablespoon melted butter and sprinkle with ¼ cup chopped parsley. Top with remaining 8 balls and another 1 tablespoon each melted butter and parsley.

Step 5

To Serve Immediately: Cover Bundt pan tightly with plastic wrap or a bowl cover; let stand in a warm place (75°F to 80°F) until rolls double in size, 45 minutes to 1 hour. Preheat oven to 350°F during last 30 minutes of rising. Uncover and bake until golden brown, 25 to 30 minutes. Immediately unmold and invert onto a wire rack. Remelt remaining 2 tablespoons butter, if needed, and stir in remaining 1 tablespoon parsley. Brush over rolls and sprinkle with flaky sea salt. Serve warm.