Prep your pan: Heat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease it.
Mix the dry ingredients: In a large bowl, whisk flour, baking powder, baking soda, salt, and cinnamon until evenly combined.
Whisk the wet ingredients: In a separate bowl, whisk eggs, oil, yogurt, milk, honey or maple syrup, and vanilla until smooth.
Add lemon zest if using.
Combine gently: Pour the wet ingredients into the dry and stir with a spatula until just combined. The batter should be thick and slightly lumpy. Avoid overmixing.
Fold in the cherries: Add the chopped cherries and fold them in lightly.
If using frozen cherries, toss them in 1 teaspoon flour first to reduce bleeding.
Fill the muffin cups: Divide the batter evenly among the 12 cups, filling each about 3/4 full. Sprinkle with rolled oats and a pinch of coarse sugar if you like.
Bake: Bake for 16–20 minutes, or until the tops are set and a toothpick comes out clean or with a few moist crumbs.
Cool: Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to finish cooling. This helps keep the bottoms from getting soggy.