Preheat the oven to 350°F (175°C) and line a 12-cup muffin pan.
Whisk flour, cocoa, baking soda, salt, and cinnamon.
Mix eggs, pumpkin, both sugars, oil, and vanilla in another bowl.
Gradually add the dry ingredients.
Stir only until a smooth batter forms.
Divide among the cupcake liners, filling each about two-thirds full.
Bake for 18–20 minutes.
Cool completely before adding your preferred frosting.