Melt 1 tablespoon butter in a large pan over medium heat. Add the diced onions and fry for 5-8 minutes until translucent.
While the onions cook, soak the slice of white bread in 125 ml of the milk for 2 minutes, then squeeze out the excess milk and add the bread to the onions.
Add 30 ml vinegar, 15 ml apricot jam, 30 ml curry powder, 10 ml salt, pepper to taste, and 3 tablespoons sliced almonds to the onion mixture. Stir well to combine.
In a separate pan, brown the 1 kg ground beef over medium-high heat for 8-10 minutes, breaking it apart as it cooks.
Add the cooked ground beef to the onion mixture and stir to combine. Taste and adjust the seasoning—add more jam for sweetness, vinegar for sourness, or curry powder for spice, as desired.
Pour the meat mixture into a baking dish.
In a bowl, whisk together the remaining 125 ml milk with 2 eggs until well combined.
Pour the egg mixture over the meat mixture in the baking dish.
Arrange 6 bay leaves in the mixture.
Preheat the oven to 160 °C (320 °F). Bake the casserole for 30 minutes until the egg custard is set.