Preheat the oven to thermostat 5 (150°C).
Crack the eggs into a bowl, add the salt and sugar, then whisk until the mixture is foamy. Gradually incorporate the sifted flour and baking powder, followed by the milk and 4 tablespoons of oil, beating until the batter is smooth and homogeneous.
Grease an earthenware baking dish with butter and pour in the batter. Bake for 10 minutes. Meanwhile, peel the apples and slice them thinly. Remove the cake from the oven, gently press the apple slices rounded-side up into the partially baked batter, packing them closely together. Return to the oven for 15 minutes.
Prepare the cream: Split the vanilla pod and scrape out the seeds into a bowl. Add the sugar, melted butter, and eggs, mixing until smooth and creamy.
After 15 minutes, remove the cake, pour the cream evenly over the apples, and bake for another 45 minutes, or until the top is beautifully golden. Remove from the oven and let cool. Serve warm or cold.
Pro Tip from the Kitchen: For the best tender texture, use a deep mold at least 5 cm high and 22 cm in diameter. A rectangular ovenproof porcelain or earthenware dish works perfectly too.
