If using dried lentils, cook 1.5 cup of dried lentils in 2 cups of water for 20 mintes until lentils are soft. Drain and set cooked lentils aside to cool.
Mix the flaxseeds and warm water in a small bowl and set aside.
Place the mushrooms and garlic into the food processor and pulse until they are finely minced.
Heat oil in a skillet over medium-high heat. Add the chopped onions and cook until they begin to brown, adding a splash of water if they begin to stick.
Stir in the mushrooms and garlic. Cover and cook until the mushrooms soften, about 2-3 minutes, stirring often.
Once the mushrooms have softened, transfer the mushroom mixture to the food processor and add the cooked lentils. Pulse until the lentils are just combined with the mushrooms.
Add the flaxseed mixture and all remaining ingredients to the food processor and pulse to combine well. The mixture should be more sticky than crumbly. If it seems too wet, add a little more oats.
Scrape the mixture into a bowl and place in the fridge for 1 hour.
Preheat the grill to 500F and place a cast iron pan or griddle on the barbeque. Add the oil to the pan.
Shape the burger mixture into 4 patties, each about 3 inches wide and 3/4 inch thick.
Place the patties on cast iron pan and cook until golden on both sides (about 4 minutes per side). Make sure they are firm in the middle but not burned.
Remove the burgers from the barbeque and serve on bun with microgreens, sliced tomato and Flora Fromage spead.