In a large bowl, combine the flour, thyme, salt and pepper. Stir in eggs until blended.
Add the sweet potatoes, parsnips and onions; toss to coat.
In an electric skillet or deep-fat fryer, heat oil to 375°. Drop batter by ¼ cupfuls, a few at a time, into hot oil; press lightly to flatten.
Fry for 3-4 minutes on each side or until golden brown. Drain on paper towels.
