Preheat oven to 425°. Julienne potatoes, turnip, and carrots using julienne attachment of food processor, or shred with box grater. Place vegetables in a strainer set over a bowl; squeeze with your hands and discard any liquid. Transfer vegetables to a bowl and stir in rosemary, garlic, egg, flour, and salt and pepper.
Line baking sheet with parchment paper. Using your hands, rub the surface with the olive oil; don't wash your hands! Use your oily hands to divide the mixture into 10 even clumps; press and shape into patties on the tray. Bake until crispy and golden on one side and the pancakes release easily from the pan (about 25-30 minutes). Flip and continue until the tops are a deep golden brown (about 15 minutes more). Serve warm, with applesauce, if desired.