Preheat oven to 350°F (175°C). Grease a 9-inch round cake pan.
In a medium bowl, mix together the butter and sugar until well blended.
Add eggs and vanilla extract and mix until well combined.
In a separate bowl, sift together the flour, baking powder, and salt.
Add the dry ingredients to the wet ingredients and mix until just combined.
Fold in the milk, apples, and walnuts until evenly distributed.
Pour the batter into the prepared pan and bake for 30 minutes, or until a toothpick inserted into the center comes out clean.
While the cake is baking, make the rum sauce. In a medium saucepan, combine the rum, brown sugar, and cream. Cook over medium heat until the sugar is dissolved and the sauce is smooth.
When the cake is done baking, remove it from the oven and let cool for 10 minutes. Serve warm, topped with the rum sauce.
Interesting Facts
Apples are a great source of dietary fiber, vitamin C, and antioxidants.
Walnuts are an excellent source of healthy fats, protein, and fiber.
Rum sauce is a classic French dessert sauce that is made with rum, sugar, and cream.