In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, kosher salt, and ground cinnamon until well combined.
2 cups all-purpose flour, 1¼ cups granulated sugar, 1 tablespoon baking powder, ½ teaspoon kosher salt, ½ teaspoon ground cinnamon
In a smaller separate bowl, whisk together the eggs, whole milk, vegetable oil, orange juice, vanilla extract, and the zest of an orange until well combined.
2 large eggs, 1 cup whole milk, 1/2 cup vegetable oil, 1/4 cup orange juice, 2 teaspoons vanilla extract, 1 tablespoon orange zest
Slowly add the wet ingredients into the bowl of dry ingredients, mixing with a rubber spatula just until combined and no flour streaks or pockets remain the batter. Be careful not to overmix.
Use a rubber spatula to gently and carefully stir in 1 cup of the frozen cranberries.
1¼ cups frozen cranberries
Allow the batter to rest for 20 minutes at room temperature.
Divide the batter evenly between the muffin cups, filling each one about 2/3 of the way full. Add the remaining frozen cranberries to the tops of the muffins (about 2-3 frozen cranberries per muffin).
Bake for 9-12 minutes or until the muffins have a domed top. Once the tops of the muffins have domed, reduce the oven temperature to 350℉ and bake for 5-6 minutes or until a toothpick inserted into the middle comes out clean.*The initial "burst" of the higher oven temperature will cause the muffins to develop that dome top quickly, once they are, you can reduce the temperature and continue cooking. Remove the muffins from the oven and allow them to cool in the muffin pan for about 10 minutes before transferring them to a cooling rack to cool completely.