Preheat your oven to 350°F (175°C)
Cream Butter with brown sugar until light and fluffy
Add eggs, one at a time, and vanilla extract.
Add dry ingredients: flour, cinnamon, and baking powder.
Mix until well incorporated and remember to scrape the sides as you go.
Peel and dice one of the apples and mix into the batter.
Pour into the baking dish of your choice.
Peel and thinly slice the other apple. Top the cake with this apple.
Topping: Mix sugar and walnuts and sprinkle over cake. Add dots of butter on top of everything.
Bake for 45 minutes to an hour. Check the cake at 45 minutes by inserting a toothpick into it, if it comes out clean, you're ready, if not, pop it back in for another 15 minutes or so.