Preheat your oven to 350°F (175°C) and grease a bundt pan.
In a large bowl, mix together the flour, sugar, baking powder, cinnamon, and salt.
In another bowl, combine milk, eggs, and vanilla extract; whisk until smooth.
Gradually add the wet ingredients to the dry ingredients, stirring until just combined.
Fold in the diced apples, brown sugar, and lemon juice.
Pour half of the batter into the prepared bundt pan.
Sprinkle some cinnamon sugar over the batter.
Add the remaining batter and smooth the top.
Bake for 45-50 minutes or until a toothpick inserted comes out clean.
Allow to cool for 10 minutes before inverting onto a serving platter.