Set aside ½ cup lentils. Pulse the remaining 2½ cups of cooked lentils in a food processor until semi-mashed, about 7-8 pulses. Add the walnuts and pulse 4-5 more times.
Transfer the lentil mixture to a large bowl. Add the oats to the food processor. Process until you reach a flour consistency, then add to the lentil mixture.
Stir in the veggies, whole lentils, and flax eggs. Mix well. Taste and add more spices, if desired.
Transfer to an oiled 9x13 pan. Press down with your hands or the back of a spoon. Top with the glaze and bake at 350F for 30 minutes. Let rest for 10-15 minutes before serving.
Notes
*Be sure to use GF vegan worchestershire if you are making this gluten-free. *Replace walnuts with pumpkin seeds if you have a nut allergy.