Preheat your oven to 325°F (163°C). Line a muffin tin with cupcake liners and spray lightly with cooking spray.
In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt. Set aside.
In a large bowl, cream together the softened butter, white sugar, and brown sugar until light and fluffy. Add the egg and beat well. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Begin and end with the dry ingredients, mixing just until combined after each addition.
Divide the batter evenly among the cupcake liners, filling each about two-thirds full.
Mix the 2 teaspoons of white sugar and ½ teaspoon of cinnamon in a small bowl. Sprinkle this mixture over the cupcake batter.
Bake in the preheated oven for about 22 minutes or until a toothpick inserted into the centre of a cupcake comes out clean.
Remove the cupcakes from the oven and let them cool in the muffin tin for a few minutes. Then transfer them to a wire rack to cool completely.
While the cupcakes are baking, prepare the crispy cinnamon topping. In a small bowl, combine the white sugar and ground cinnamon. Pour the melted butter over the mixture and stir until it resembles wet sand. Spread the mixture evenly on a baking sheet lined with parchment paper. Bake for about 8 minutes or until golden brown and crispy. Remove from the oven and let it cool completely. Once cooled, break the topping into small crumbles.
In the meantime, prepare the lemon cream cheese frosting. In a large bowl, beat the softened cream cheese and butter until smooth and creamy. Gradually add the powdered sugar, vanilla extract, and lemon zest. Beat until well combined and creamy.
Once the cupcakes are fully cooled, frost them with the lemon cream cheese frosting.
Just before serving, top the cupcakes with some fresh lemon zest and a sprinkle of the prepared crispy cinnamon topping.
Enjoy your delicious Killaloe Sunrise-inspired cupcakes with their fluffy texture, zesty lemon cream cheese frosting, and crunchy cinnamon topping.