01 -
Preheat oven to 350 degrees Fahrenheit and lightly coat a 10×15 inch jelly roll pan with nonstick spray.
02 -
In a medium saucepan, bring butter and water to a boil, stirring frequently to avoid burning. Remove from heat and let cool slightly.
03 -
In a large bowl, whisk together flour, granulated sugar, salt, baking soda, and cinnamon.
04 -
In a separate bowl, whisk together sour cream and eggs until fully combined.
05 -
Add the sour cream mixture to the dry ingredients and stir to form a thick batter.
06 -
Fold in the diced or grated apples until evenly distributed.
07 -
Gradually stir in the cooled melted butter and mix until fully incorporated and batter loosens.
08 -
Pour batter into the prepared pan and bake for 25 to 27 minutes, or until the center springs back when lightly touched.
09 -
Remove from oven and allow cake to cool until just slightly warm.
10 -
Combine butter and milk in a microwave-safe bowl and heat for 45 seconds, then in 15-second intervals until butter is melted. Whisk to combine.
11 -
Add powdered sugar, vanilla extract, and caramel sauce to the bowl and whisk until smooth. Adjust consistency with more sugar or milk as needed.
12 -
Pour icing over the slightly warm cake and spread evenly. Let set fully before slicing.
13 -
Cut into squares and serve.