In a large bowl, whisk together the flour, polenta, baking powder and salt. In a large measuring cup, whisk together the buttermilk, ricotta, lemon zest and eggs. Pour the liquid ingredients over the dry ingredients and fold together, using a rubber spatula, until just combined. Let sit for 15 minutes to allow the polenta to soften.
Preheat a rimmed griddle to medium-low heat. Add oil to coat the griddle.
With a 1/4-cup measure, scoop batter onto the griddle. Cook for 2 to 3 minutes per side, until golden brown and cooked through. Remove the pancakes to a plate and continue with the remaining batter. Serve warm with lots of warm maple syrup.