Place the grated potatoes in a clean kitchen towel and squeeze out as much moisture as possible.
In a large bowl, combine the grated potatoes, finely chopped onion, eggs, flour, and baking powder. Season with salt and pepper. Mix until well combined.
In a large skillet or frying pan, heat a generous amount of vegetable oil over medium-high heat.
Drop spoonfuls of the potato mixture into the hot oil, flattening them slightly with the back of the spoon. Fry until golden brown and crispy, about 3-4 minutes per side. You may need to do this in batches to avoid overcrowding the pan.
Remove the fried Bulviniai Blynai from the skillet and place them on a paper towel-lined plate to drain excess oil.
Enjoy your meal!