Yes, it is possible. Once you add the milk, eggs, and butter, you should mix the batter until everything is just combined. This is to avoid the flour in the batter becoming too developed, which will cause the cornbread to have tunnels and a tough texture. After the batter is mixed you will add the zucchini, so be careful that you incorporate it until just combined as well, since everything will already be mixed together. For tender and soft cornbread, don’t overmix!