1. Preheat oven to 425°F. Generously grease 12-14 muffin tin cups with butter or cooking spray, or line with muffin liners.
2. In a large bowl, whisk together flour, poppyseeds, baking powder, baking soda, and kosher salt. Set aside.
3. In a separate large bowl, combine granulated sugar and orange zest. Using an electric mixer, mix the sugar and zest together for about 20 seconds to help release the citrus oils.
4. Add melted and cooled butter, neutral oil, room temperature eggs, and vanilla extract to the sugar mixture. Mix well until thoroughly combined.
5. Add the dry ingredients to the wet ingredients and mix until about halfway combined.
6. Pour in the orange juice and gently mix until just combined. Do not overmix – the batter should be slightly lumpy.
7. Fill muffin cups near to the top of each tin for the best rise and dome shape.
8. Bake at 425°F  for 5-7 minutes, then without opening the door, reduce the heat to 375°F and continue baking for 12-15 more minutes. Total bake time is 18-21 minutes.
9. The muffins are done when they have a nice dome and a toothpick inserted in the center comes out clean or with just a few moist crumbs.
10. If desired, brush with melted butter right when they come out of the oven.
11. Cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

Notes

• For best results, use room temperature eggs and orange juice. Be sure that your melted butter isn’t too warm when adding it to the mixture to avoid scrambling the eggs.
• The high initial baking temperature creates the signature muffin dome – do not open the oven door during the first phase of baking. If you prefer, you can also bake the muffins at 375°F for 21-24 minutes total, but they won’t have as much of a rounded dome top.
• Store covered at room temperature for up to 3 days or freeze for up to 3 months, wrapped tightly. Defrost at room temperature.