An inspired way to use up leftover rice! The grains are amped up with grated zucchini, Parmesan, lemon zest, and fresh mint before being fried into a golden brown pancake.
In a bowl, thoroughly combine rice, zucchini, Parmesan, eggs, lemon zest, sliced mint, 1 teaspoon salt, and 1/4 teaspoon pepper.
Heat 1/4 cup oil in a large nonstick skillet over medium-high. When it shimmers, pour rice mixture into center and press with the back of a spoon until flattened to a 1/2-inch-thick pancake. Cook until bottom is golden brown and edges are crisp, 4 to 5 minutes (lower heat if edges are browning too quickly). Carefully flip with large spatula, or slide onto a plate, flip onto another plate, and slide back into skillet. Cook on second side until golden brown, 3 to 4 minutes more. Transfer to a cutting board.
In a bowl, toss together celery, radishes, lemon juice, and remaining 2 teaspoons oil. Season with salt and pepper. Arrange avocado on cake; season with salt. Top with salad, celery leaves, and mint leaves. Cut into wedges; serve.
While it's impressive to serve the rice as one large round cut into wedges, you can also divide the mixture into four equal portions and fry individual rice cakes.