Preheat oven to 350℉ and place about 8 jumbo cupcake liners into a jumbo muffin tin. (You may need to bake in two batches if you only have a tin with 6 cavities.)
In a large bowl, combine granulated sugar (½ cup), vegetable oil (½ cup), vanilla extract (1 teaspoon), shredded zucchini (1 cup), unsweetened cocoa powder (¼ cup), and eggs (2 large) and stir until just combined.
Add cinnamon (½ teaspoon), salt (½ teaspoon), and baking soda (½ teaspoon) and stir gently until it disappears into the batter.
Using a spatula, gently add in the all-purpose flour (1 ½ cups) and only stir until the dry ingredients disappear and are incorporated into the batter. It is important to mix this by hand (and not an electric mixer) to prevent from over mixing.
Gently fold in the ½ cup of semi-sweet chocolate chips until evenly dispersed.
Scoop about 6 tablespoons of batter into each muffin tin and gently tap the muffin tin on the counter to smooth out the tops of the batter.
Bake at 350℉ for 25-30 minutes or until fork comes out clean. Overbaking can result in dry and hard muffins, so watch the oven closely around the 25 minute mark.
Once baked, allow the muffins to cool on a wire rack for 5-10 minutes before removing from the pan. These are best enjoyed warm, so dig right in!