I don't know the secrets of the brown, but they sell plenty of decent Vindaloo spice pastes that they generally direct you to add canned tomatoes and some sauteed onion to, plus the meat. If you want more sauciness to your curry than that gives, then I like the brown a whole bunch of onions down to onion soup consistency, add some garlic and ginger and sautee that quickly, then take that out, add canned tomatoes, add spice paste, and blend the whole lot. Brown your meat in the pan alone, pour caramelized onion and spiced tomato mix over, add some potatoes if you like. Simmer it til the meat tenders and potatoes turn soft. While its cooking you can adjust the sour/sweet using wine vinegar and sugar, and then if you like a bit more spice kick, then add a pinch of spices toward the end - curry powder, garam masala, chile powder, cumin, turmeric, depending on what you want. Stir in minced cilantro before serving to let it wilt a quick second.