Preheat the oven to 385°F (195°C) and line a 12-cup muffin pan with liners. For the best rise, either fill every other cup or place them side by side if you're in a hurry.
Prepare the citrus sugar by combining the sugar and orange zest in a bowl. Rub them together between your fingers to release the zest’s fragrant oils and infuse the sugar with bright citrus flavor.
Mix the wet ingredients in a separate bowl by whisking together the milk, white vinegar, yogurt and fresh orange juice until well combined. Stir in the sugar and zest mixture, ensuring everything is fully incorporated.
Add the oil and vanilla extract to the wet mixture, whisking until smooth and silky.
Prepare the dry ingredients by sifting together the flour, baking powder, baking soda, and salt in another bowl.
Combine the wet and dry ingredients by gradually folding the dry mixture into the wet. Stir just until combined—be careful not to overmix!
Fold in the fresh cranberries (if using) gently, adding little bursts of tart sweetness throughout the batter.
Cover and Let the batter rest for 30 minutes in the fridge to develop flavor and texture.
Fill the muffin liners to the top and generously sprinkle with coarse sugar for a bakery-style crunch.
Bake for 17-18 minutes until the muffins are golden, firm to the touch, and a toothpick inserted in the center comes out clean.
Let the muffins cool slightly, then enjoy every fluffy, citrusy bite!