Heat a large skillet with 1 tbsp of olive oil and saute your diced onions until they soften, about 5-7 minutes.
Transfer them to a bowl with the grated carrots, lentils, garlic and spices and mix well using your hands. The lentils don't need to be fully mashed.
Add in the soy sauce, ketchup and oat flour and mix well together until evenly incorporated.
Line a cutting board or plate with parchment paper. With oiled hands, shape the batter into 6 palm-sized burgers.
Heat your skillet on medium/low heat, and add in another 1-2 tbsp of olive oil. Cook the lentil burgers for about 5-6 minutes per side, until golden brown. I suggest cooking 3 at a time, depending on the size of your skillet, and adding more oil in between batches.
While they cook, prepare the yogurt dip by mixing together the yogurt, crushed garlic, lemon juice, parsley and salt.
The burgers will stay fresh in the fridge for up to 5 days, or can be frozen for 3 months.