01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease each cup.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt until well combined.
03 - In a separate bowl, combine ricotta cheese, eggs, milk, melted butter, orange zest, orange juice, and vanilla extract. Whisk until smooth.
04 - Pour wet ingredients into the dry mixture and gently fold until just combined. Avoid overmixing; a few lumps are acceptable.
05 - Divide batter evenly among the muffin cups, filling each about three-quarters full.
06 - Sprinkle tops with coarse sugar and extra orange zest as desired.
07 - Bake for 18 to 22 minutes or until a toothpick inserted into the center comes out clean.
08 - Allow muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.