For the cake:
3 cups all-purpose flour, sifted
1/4 cup sugar
2 tablespoons ground cinnamon
3 teaspoons baking powder
1 teaspoon salt
2 medium apples, peeled and chopped
1 (12-ounce) bottle of beer or unsweetened apple juice, room temperature
1/4 cup butter, melted
For the icing:
2 cups confectioners' sugar
3-5 tablespoons milk, 2%
1/2 teaspoon vanilla extract
Preheat the oven to 350 degrees F.
Line an 8-inch square baking pan with parchment, letting the ends extend up the sides.
In a large bowl, whisk together the flour, sugar, cinnamon, baking powder, and salt.
Add the apples and beer to the dry mixture, mixing until it is just blended. Be careful not to overmix, the batter will be thick.
Transfer the batter to the prepared baking pan.
Bake until a toothpick inserted in the center comes out clean, about 40-45 minutes.
Carefully lifting with the parchment paper, immediately transfer the cake out of the pan.
Brush all sides with the melted butter.
Allow the cake to cool.
While the cake is cooling, in a small bowl, combine the confectioners' sugar, milk, and vanilla extract.
Spread or drizzle the icing over the cooled cake.
Serve.