In a small bowl, combine warm milk and active dry yeast. Let it sit for about 5-10 minutes or until it becomes frothy.

In a large mixing bowl, combine the softened butter and granulated sugar. Cream them together until light and fluffy.

Add the eggs and vanilla extract to the butter and sugar mixture. Mix until well combined.

Pour the yeast and milk mixture into the bowl with the wet ingredients and mix to combine.

Gradually add the flour and salt to the wet ingredients, mixing until a dough forms. You may need to knead the dough with your hands for a few minutes until it's smooth.

Divide the dough into 8 equal portions and shape them into balls. Place them on a baking sheet lined with parchment paper and let them rest for about 10 minutes Covered with saran wrap

While the dough is resting, prepare the concha topping (streusel). In a mixing bowl, combine the flour, powdered sugar, softened butter, and vanilla extract. Mix until you have a smooth paste. If you want colorful toppings, divide the streusel into separate bowls and add food coloring to each portion.

Roll the streusal topping out to about ⅛” thick and cut into circles that will be large enough to cover the dough ball

Flatten each dough ball slightly and place a cut out streusel circle on top, pressing it down gently. Use a sharp blade to cut the shape of a shell into just the streusel topping. Cover the conchas with saran wrap and allow to rise one more time for 1-2 hours.

Preheat your air fryer to 350°F (175°C).

Lightly grease the air fryer basket with cooking spray or oil.

Place the conchas in the air fryer basket, ensuring they don't touch each other. Depending on the size of your air fryer, you may need to cook them in batches.

Air fry the conchas at 350°F (175°C) for about 8-10 minutes or until they are golden brown and the streusel is slightly crispy.

Remove the conchas from the air fryer and let them cool on a wire rack.