Preheat the oven to 200 degrees.  Using the large holes on a box grater or the grater function of your food processor, grate sweet potatoes and onion.

Crack eggs into a large bowl and beat lightly.  Add grated vegetables, flour, thyme, salt and a few grinds of pepper.  Stir to combine.

Heat 3 tablespoons of olive oil in a large nonstick skillet over medium heat until shimmering.  Add ¼ cup of mixture to the pan at a time, pressing down slightly with the back of the measuring cup to flatten into ½-¾ inch thick cakes. You should be able to fit 6 cakes in the skillet at a time.  Cook until golden brown, crisp and cooked through, about 8 minutes total, flipping cakes occasionally.  Lower the heat as necessary if the cakes are browning too quickly.

Transfer to a rimmed baking sheet lined with paper towels.  Sprinkle with sea salt flakes and transfer to the oven to keep warm.

Wipe out the skillet with a damp paper towel and add the remaining 3 tablespoons of olive oil.  Repeat the process with the remaining mixture.

Serve cakes with bacon and Stirred Lingonberries or lingonberry preserves or jam.