Preheat oven to 350F (180C), and lightly grease and line a 9 inch pan.
Toss the apple cubes with lemon juice, lemon zest, and 1/4 teaspoon of cinnamon powder. Set aside.
In a large bowl, whisk together the remaining 1/4 teaspoon cinnamon, the flour, sugar, baking powder and nutmeg if using. Set aside.
In another bowl, whisk the eggs, vanilla, olive oil and milk. Pour the wet ingredients into the dry, and mix to combine. Don't over mix, once most of the flour is incorporated, fold in apples.
Spread batter into prepared pan, sprinkle with extra sugar if you like, and bake for 30-35 minutes until toothpick inserted in the center comes out clean.
Enjoy room temperature or cool, it's delightful either way!