For the marinade: Pull out your pestle and mortar and add the caraway seeds. Grind to a powder, then pour into a large non-reactive bowl (stainless steel is best because turmeric can stain ceramics). Add the garlic and the ginger to the mortar. Sprinkle with a little salt and pound away until a relatively smooth paste forms. (If you don't have a pestle and mortar then finely mince the ginger.)
Scrape the ginger-garlic paste into the large bowl with the caraway seeds. Add the yoghurt, 1 teaspoon of salt, turmeric, cayenne pepper and garam masala and whisk all together. Add the lamb and toss until all the pieces are well coated. Cover the bowl with plastic wrap, place it in the refrigerator and let it marinate up to overnight.
When you're ready to cook, preheat the oven to 200°C.
Pull out the lamb and let it come to room temperature. Meanwhile, get going on the onions. Warm the oil in a large skillet over high heat. Add the onions and stir so they're thoroughly coated with oil. Let them sit about 5 minutes or so, until the onions around the perimeter begin to brown. Stir, redistribute, and allow to sit another 5 minutes or so. Repeat this process until the onions are evenly browned, about 20 minutes in total.
Reduce the heat to low and cook another 20 minutes, stirring occasionally, until the onions are a deep chestnut brown (not burnt!) and slightly crispy. Using a slotted spoon, remove the onions to a paper towel-lined plate and drain. (You can strain the oil and use it to cook your next batch of vegetables!).
Add the onions to the lamb along with the milk and the dried apricot halves. Stir to combine evenly, then pour into a medium baking dish that holds the lamb in a single, even layer (an 8-inch square or an 8-inch by 10 1/2-inch dish works well as does an oval dish). Cover firmly with foil, and pop into the oven for 1 1/2 hours, rotating the dish halfway through the cooking time, uncover for another 30 minutes of cook time.
Sprinkle with almonds and serve with crusty bread or naan.
For the garam masala
Combine the cinnamon sticks, cloves, green cardamom seeds, black cardamom seeds, if using, in a spice grinder or coffee grinder and grind until fine. Store the spice mix in an airtight container away from direct sunlight.