How to Make It
Combine flour and salt on a flat surface, using fingers. Make a well in center of mixture, and add egg, oil, and 3 tablespoons water. Using fingers, incorporate flour gradually until a soft dough forms. Knead dough on a lightly floured surface 3 to 4 minutes or until smooth and elastic. Cover with plastic wrap, and let stand at room temperature 1 hour.
Meanwhile, pierce potato several times with tines of a fork. Place on a microwave-safe plate; cover with damp paper towels.
Microwave at HIGH 10 minutes or until tender. Let stand 5 minutes; peel potato, and mash with a fork or potato masher. Stir in 2 tablespoons butter. Season with salt and pepper to taste.
Sauté onion in remaining 2 tablespoons butter in a medium Dutch oven over medium heat 7 minutes or until tender. Add ham and garlic; sauté 1 minute. Stir in collard greens and next 3 ingredients, tossing to coat; stir in 11 cups water. Bring to a boil over medium-high heat. Reduce heat to medium-low, and simmer 45 minutes or until greens are tender.
Meanwhile, attach pasta maker attachment to electric stand mixer according to manufacturer's instructions. Divide dough into 2 equal portions. Flatten into disks. Feed dough disks into pasta maker, 1 at a time, adjusting pasta sheet roller and mixer speed as you work according to manufacturer's instructions. Lay pasta sheets on a lightly floured surface.
Dollop level tablespoonfuls of potato mixture 1 1/2 inches apart on 1 pasta sheet. Brush egg white around filling on pasta sheet; top with remaining pasta sheet. Gently press pasta sheets together around filling to seal, removing any air pockets. Using a ravioli cutter or a knife, cut pasta sheets into 3- x 2-inch ravioli. Place ravioli on a lightly greased jelly-roll pan. Sprinkle with flour to prevent sticking, if desired. Cover with a damp cloth. Repeat procedure with remaining potato mixture and pasta sheet scraps, rerolling scraps as directed in Step
Cook ravioli, in batches, in boiling salted water to cover 2 minutes or until ravioli float to top; drain. Place 2 ravioli in each of 9 shallow serving bowls. Top with collard green mixture. Serve immediately.