In a large bowl, whisk together 1 cup (120 g) self-rising flour, 2 tablespoons (25 g) sugar, 1/4 teaspoon (0.6 g) kosher salt, and 2 tablespoons (11 g) unsweetened cocoa powder until evenly combined.
In a separate bowl, whisk 1 cup (245 g) buttermilk, 1 (50 g) egg, 2 tablespoons (28 g) melted butter, and 1 teaspoon (5 g) vanilla extract until smooth.
Pour the wet mixture into the dry mixture and gently fold with a spatula or spoon until just combined; small lumps are fine—do not overmix.
Heat a nonstick griddle or skillet over medium heat until hot.
Using a 1/4-cup measuring cup, pour portions of batter onto the hot griddle, leaving space between pancakes.
Cook until bubbles form on the surface and the edges look set, about 2–3 minutes.
Flip each pancake once and cook until the second side is golden and the pancake is cooked through, about 1–2 minutes more.
Transfer pancakes to a plate and serve hot.