Rinse and dry apples, cut into quarters, peel and core. Cut quarters crosswise into slices. Combine apples with lemon juice and 2 tablespoons of sugar and bring to a boil. In another pot, bring to a boil milk with 2 tablespoons of sugar. Add rice, sprinkle with grated lemon zest and cook, covered, on very low heat for 30 minutes. Turn off heat and let stand for another 10 minutes until rice plumps up.
Beat egg yolks and butter until fluffy, add to rice pudding.
Add drained apples.
Beat egg whites until stiff and fold into rice. Butter casserole dish and pour in rice pudding. Sprinkle with almonds. Bake in a preheated oven at 200°C (approximately 400°F) for about 30 minutes. Cut into portions and serve.