For the cake, grease and flour bundt pan (or use a generous amount of baking spray). Set aside. Preheat oven to 350°F.
In a large mixing bowl, combine flour, sugar, baking powder, baking soda and salt. Add in softened butter and beat until crumbly. Beat in eggs, vanilla, cinnamon and milk. Beat for 3-4 minutes until smooth and fluffy.
In a small mixing bowl, combine diced apples, brown sugar and cinnamon. Fold into cake batter.
Pour cake mixture into prepared bundt pan. Bake for 55-60 minutes until browned. Allow to cool in pan for about 10 minutes, then flip onto a cake plate and cool complately.
For the glaze, add brown sugar, butter and 4 Tbsp of milk to a small saucepan. Heat over medium until boiling. Stirring constantly, boil for 2 full minutes. Remove from heat. Add in vanilla extract. Allow to cool 15 minutes.
In a mixing bowl, whisk together cooled sugar mixture, powdered sugar, and remaining 2 Tbsp milk. Beat for 2 minutes until smooth. Pour over cooled cake and allow to set (about 10 minutes). Slice and enjoy.
Notes
Store cake in airtight container at room temperature for up to 5 days. Or freeze for up to 3 months.
Let the icing on the Caramel Apple Bundt Cake set for 10 minutes before slicing and serving.