To begin, preheat your oven to 425. Line a muffin tin with cupcake wrappers or spray with non-stick spray.
To a large mixing bowl, add your butter and sugar and beat together with a mixer till creamy. Add your yogurt, milk, orange juice, orange zest and vanilla and mix together till smooth. Add your eggs and briefly blend in.
To the same bowl, add your flour, baking soda and salt. Mix together till you have a consistent muffin batter.
Fill each muffin cavity about 3/4 way full with batter. Bake at 425 for 5 minutes. Then, lower the oven temperature to 350 and bake for another 14-16 minutes, or till the tops are springy to touch and a toothpick inserted comes out clean.
Let cool before removing and topping with glaze.
To a small bowl, add your powdered sugar and 4 tsp of milk. Whisk together till smooth. If necessary, add another tsp of milk. Drizzle on top of each muffin.
Devour!
Stored in an airtight container in the fridge, these will last about a week. They will last about 2-3 days stored at room temperature.