Step 1

Add lemon juice to a cup of milk. Set aside until milk starts to curdle, 5 to 10 minutes.

Step 2

Combine flour, sugar, cinnamon, baking powder, baking soda, and salt in a large bowl. Make a well in the center. Pour in curdled milk, egg, melted butter, and vanilla extract. Stir with a spoon or whisk until the batter is just combined. Add shredded zucchini and mix until well incorporated.

Step 3

Heat a large skillet over medium heat, and coat with cooking spray. Pour 1/4 cupfuls of batter onto the skillet, and cook until bubbles appear on the surface, about 2 minutes. Flip with a spatula, and cook until browned, about 2 more minutes.