Preheat oven to 350 degrees F.
Finely chop the apples. You should have enough to equal about 2 cups. Set aside.
In a separate bowl, sift together flour, baking powder, salt and cinnamon. Set aside.
In the bowl of a standing mixer, or in a large mixing bowl with a hand mixer, combine eggs, oil, sugar and vanilla. Beat 2 minutes.
In two batches, add the flour mixture to the egg/oil mixture beating well and scraping sides of the bowl between additions.
With mixer on lowest speed, fold in the apples. Batter will be stiff but pourable
Fold batter into prepared bundt pan. Bake for 45 minutes or until a knife inserted in center of cake comes out clean.
Cool 10 minutes in pan. Put out onto cooling rack. Cool completely.
While cake is cooling, prepare the glaze.
Melt 4 tablespoons butter in a sauce pan. Add ½ cup brown sugar and whisk until mixed.
Slowly drizzle in 1/3 cup milk while still whisking. Bring to a boil, stirring constantly. Boil for
4 – 5 minutes.
Remove from heat and let cool. The glaze will thicken as it cools.
Place cake (still on the cooling rack) on a large cookie sheet.
Pour the glaze over the cake and let harden a bit before serving.