In a large bowl, place potatoes and 1/4 teaspoon of salt; mash until smooth. Add flour, a little at a time, gently kneading the flour into the potatoes. Add enough flour until the dough is firm and not sticky (you may not need to add the entire 2 cups of flour). Test the dough by pinching off a small piece and adding it to the boiling water. The dough should stay intact--if it falls apart, add more flour. On a lightly floured work surface, roll the dough into a 1-inch diameter rope. Cut dough into 1-inch pieces; roll into balls. Flour the back of a dinner fork, and roll the dough with your thumb from top of the fork to the bottom, making an indentation with your thumb and fork--one side should have lines and the other side, a dimple. Place gnocchi on a floured dish; refrigerate until ready to use. In a saucepot, bring water (enough to cover the gnocchi) and the 1 tablespoon salt to a boil. Add gnocchi. As the gnocchi float to the top, remove with a slotted spoon; drain well. To serve, place gnocchi in a bowl, top with Plum Tomato, Garlic, and Basil Sauce; garnish with fresh grated Parmesan cheese and drizzle with olive oil if desired. Makes 2 to 3 servings.
Plum Tomato, Garlic, and Basil Sauce:
Remove skins from tomatoes by cutting out the stem and cutting an X on the bottom of each tomato. Drop tomatoes into boiling water for 1 to 2 minutes or until the skins split. Remove tomatoes and immediately place in a bowl of ice water to cool. With a paring knife, peel off the skin and cut tomatoes into halves. Squeeze seeds from tomatoes; discard seeds. Dice the tomatoes. Heat a medium skillet, add oil and garlic, sauté until lightly brown. Add white wine; reduce by 1/2. Add tomatoes and basil; reduce the heat and simmer for 10 to 15 minutes. Add salt and pepper to taste.