Combine the chopped apples with the San Antonio Dulce de Leche, and the cinnamon, mix well to coat the apples. Set aside.
Pre-heat the oven to 350ºF.
Spread butter all over a 10 to 12-cup bundt pan. Then sprinkle with flour to coat. Make sure each crevice of the bundt pan is coated in butter and flour.
Sift together the flour, cornstarch, baking powder, cinnamon, nutmeg, and salt. Set aside.
Place the oil, eggs, and sugar in a bowl. Whisk until very well incorporated.
Add the sour cream and vanilla and whisk well.
Add the sifted dry ingredients to the bowl in 3 additions, to ensure the batter isn’t lumpy. Mix very little, just enough to incorporate the flour each time. Once the mixture is smooth, stop mixing.
Pour 1/3 of the batter on the bottom of the bundt pan.
Spread half of dulce de leche coated apples on top, right in the middle of the batter, without touching the edges, so the apples and dulce de leche don’t leak out.
Top with another 1/3 of the batter.
Repeat with the remaining dulce de leche coated apples.
Then top with the remaining batter.
Bake in the pre-heated oven for about 30 minutes.
At this point place a piece of foil on top, so the cake doesn’t brown too much. Continue to bake for another 20 to 30 minutes, until a toothpick inserted in the cake comes out clean. Remove from the oven. Let the cake sit in the bundt pan for 10 minutes.
Flip it over onto a plate or cooling rack. Let the cake cool completely.
Glaze: Place the San Antonio Dulce de Leche (Original Recipe), and milk together in a bowl. Microwave for about 15 seconds, and whisk to incorporate.
Sift the powdered sugar and add it to the milk/dulce de leche mixture and whisk until smooth.
The glaze shouldn’t be too thick, and shouldn’t be too thin. It should have a pouring consistency, so that when you pour it over the cake it drips down to the side, without melting all over the place. Test by spooning a drop of the glaze on the side of the cake. If it starts to drip and stops at about halfway down the side of the cake, the glaze is good to go, you can pour it. If the glaze isn’t dripping at all, it needs to be thinner, so add about 1/2 tsp of milk at a time, and whisk until you achieve the perfect consistency. It should be a minimal addition of milk at a time, a little goes a long way. If the glaze is too thin, and runny, add more powdered sugar and whisk. Continue to add powdered sugar until the glaze is thick enough.