Preheat your oven to 350 °F (180 °C) and prepare a baking tray with parchment paper and set aside.
Make the flax egg by mixing the ground flaxseed with the water and set aside to thicken for 3-5 minutes.
Add the cooked lentils and remaining ingredients to a bowl and mix together until all of the ingredients are well combined.
Once the mixture has formed, use a tablespoon and your hands to gently form the meatballs.
When the meatballs are formed, heat a skillet over medium heat and add 1 tablespoon of oil. Gently place the meatballs into the pan and allow them to brown on each side – repeat with the remaining oil until finished. Place the meatballs onto the baking tray as they are finished browning.
Once all the meatballs have been browned, place the baking tray into the oven and allow the meatballs to finish cooking through for 10-15 minutes.
Remove meatballs from the oven and allow them to cool slightly (about 5 minutes) before serving. From here you can cover them with your favorite sauce and serve with your favorite pasta.