In a large saucepan, cook the turnips and sweet potato for 15 minutes or until fork-tender. Remove from water and let cool in a large mixing bowl.

Mash turnips and sweet potato with a fork, then stir in scallions, egg and flour.

For frying: Heat grapeseed oil in a large pan over medium-high heat until shimmering but not smoking. Add 1/4 cup turnip-potato mixture to the pan and flatten with back of the measuring cup. Cook 3-4 minutes per side until browned. Remove and let cool on a paper towel lined plate.

For baking: Preheat oven to 375 degrees. Line a baking sheet with parchment paper and measure out 1/4 cup turnip-potato mixture onto parchment paper, flattening into a patty with back of measuring cup. Bake 15 minutes per side.