In a large bowl, mix together the flour, baking soda, baking powder and salt. Set aside.
3 cups all purpose flour, 3 teaspoons baking powder, ½ teaspoon baking soda, ½ teaspoon kosher salt
In another bowl, whisk together the eggs, buttermilk, vanilla extract, oil and sugar. Whisk for 1 minute.
1 cup buttermilk, ½ cup neutral oil, 2 teaspoons vanilla extract, 2 large eggs, 1 cup white sugar
Pour the wet ingredients into the dry ingredients and fold until just combined. Cover the bowl with plastic wrap and let rest at room temperature for about an hour.
Filling
Whisk the cinnamon sugar filling ingredients together in a small bowl and set aside.
¼ cup light brown sugar, ½ teaspoon ground cinnamon
Streusel
In a jug or medium bowl, mix the melted butter with the remaining streusel ingredients. It should become thick and clumpy. Place in the fridge while you wait for the muffin batter to finish resting.
¼ cup unsalted butter, ¾ cup all purpose flour, ¼ cup light brown sugar, 1 teaspoon ground cinnamon, ¼ teaspoon ground cardamom, ¼ teaspoon kosher salt
Assembly
Preheat the oven to 425℉/220℃ (convention setting, not fan). Line a muffin pan with 6 muffin liners or grease 6 of the muffin cavities. This recipe makes 10-11 muffins but you're baking them 6 at a time. I recommend lightly greasing the top of the pan too so the muffin tops don't get stuck.
Remove the plastic wrap from the muffin batter bowl. Using a medium cookie scoop or a spoon, gently scoop out 1 ½ tablespoons of muffin batter and place in the prepared muffin pan. Sprinkle over ½ teaspoon of cinnamon sugar filling.
Scoop out another 1 ½ tablespoons of muffin batter and place on top of the cinnamon sugar filling. At this point you should have filled the liners up to the top.
Sprinkle over the chilled streusel topping. You may need to use a fork or your hands to break it up. Sprinkle over a bit of extra cinnamon sugar filling.
Bake 6 at a time for 5 minutes at 425℉. Then, without opening the oven door, lower the temperature to 350℉/175℃ and bake for another 18-20 minutes.
Remove from the oven once golden brown and let cool in the muffin pan for 5-10 minutes. Transfer the muffins to a wire cooling rack to cool completely.
Cream Cheese Glaze
Whisk all of the glaze ingredients together in a small bowl. If the glaze is too thick, drizzle in some extra heavy cream. If too thin, add more powdered sugar.
3 tablespoons cream cheese, 3 tablespoons heavy cream, 1 cup confectioners' sugar
Drizzle the glaze on top of the cooled muffins and enjoy!
Video
Notes
My recipes have been developed and tested in metric grams. I highly recommend using a weighing scale and measuring out your ingredients the metric way. Cardamom: If you can't find ground cardamom you can swap it out for ground ginger.Salt: If you don’t have kosher salt, halve the amount of salt called for in the recipe. 1 teaspoon kosher salt = ½ teaspoon fine salt. Please note I am using Diamond Crystal Kosher Salt and not Morton Salt, which is a coarse kosher salt. Coarse kosher salt is much too salty for this recipe. Oil: make sure you use a neutral oil like sunflower, vegetable or canola oil. Baking 6 at a time: by only filling every other muffin cavity, you'll get much taller muffins. I don't recommend baking them 12 at a time.