In a small bowl, combine water and 1 teaspoon of sugar. Sprinkle yeast over water and set aside for 5 minutes or until yeast becomes foamy. Stir.
In the bowl of a stand electric mixer fitted with the hook attachment, mix 2 tablespoons of sugar, flour, and salt. Add mashed potatoes and yeast mixture. Mix for 1 minute. With the mixer running at medium-low speed, slowly add 6 tablespoons of olive oil. Increase the speed to medium and mix for 5 minutes or until a dough forms.
Lightly grease a large bowl with olive oil and place the dough in the bowl. Cover with a kitchen towel and allow the dough to rise at room temperature until doubled in size, about 1 hour.
Turn the rested dough onto a lightly floured surface and work the dough until it deflates. Using a bench scraper or a knife, cut the dough into 12 even pieces. Roll each piece into a smooth ball.
Lightly grease a 13x9-inch baking dish with olive oil. Place dough balls in the pan. Leave space between them because they will grow in size. Cover with a kitchen towel and allow the rolls to rest at room temperature for 45 minutes.
Preheat oven to 400°F. Brush rolls with olive oil and sprinkle with sea salt flakes. Bake for 20-25 minutes or until golden brown. Remove from oven and brush with more olive oil and sprinkle rosemary. Serve warm.