In a large mixing bowl combine the zucchini, carrots, onion, sage, flax eggs, flour, one teaspoon of salt, and pepper. Stir until it turns into a sticky ball. Scoop a quarter cup of batter and use your hands to form patties. Place on the baking sheet and squeeze the lemon juice evenly over the top of each patty. Bake for approximately 15 to 20 minutes, checking every ten minutes, until they’re golden brown. Flip, squeeze lemon juice on top of each patty, and bake until golden brown. Remove from oven and let sit for 5 minutes.