Oatmeal and apple tart with meringue

Name: Oatmeal and apple tart with meringue
Cook time: 1 h
Total time: 1 h
Yield: 24
Ingredients: 1.2 kg Apples; 7-10 Tbsp Juice of 1 lemon; 250 g Butter or margarine; 425 g Sugar; 1 pinch Salt; 4 Eggs (size M); 350 g Flour; 1/2 package Baking Powder; 5 Protein (size M); 100 g tender oats; 7-10 Tbsp Grease