Preheat and prep. Heat your oven to 375°F (190°C) and line a muffin tin with paper liners. Yes, you really do need to preheat—don’t test fate.
Mix the dry ingredients. In a large bowl, whisk flour, cocoa powder, sugars, baking powder, baking soda, and salt. Make sure there are no cocoa clumps hiding in there.
Combine the wet ingredients. In another bowl, whisk eggs, milk, oil (or butter), and vanilla until smooth. Nothing fancy—just cohesive and happy.
Bring it together. Pour the wet ingredients into the dry and gently fold until just combined. Stop when you no longer see dry flour. Overmixing is the enemy.
Add the good stuff. Fold in dark chocolate and cherries. Try not to eat too many straight from the bowl. Or do. I won’t tell.
Fill and bake. Scoop batter into liners, filling about ¾ full. Bake for 18–22 minutes, until a toothpick comes out with a few moist crumbs.
Cool slightly. Let muffins cool for 5–10 minutes. Yes, waiting is hard. Yes, it’s worth it.