In a pan, dry roast the black peppercorns and fennel seeds till fragrant (maintain low heat to avoid the spices from burning). Allow to cool and then grind to a fine powder.
Heat 2 tbsp oil in the same pan and add the paneer pieces. On medium heat, fry the paneer till light/golden brown and keep aside. Add the bell peppers and fry for a minute; keep aside. If the paneer is not too soft, place the fried paneer in a bowl of cold water to prevent it from getting too hard.
Heat the remaining oil in a kadai/wok or a heavy bottom pot/handi. Add cumin seeds and green cardamom and fry on low heat till fragrant.
Then add the grated ginger, garlic and onions; sauté till the onions are light brown.
Next add the tomatoes and cook till the tomatoes are completely broken down and mushy.
Add all the spice powders and sugar; continue to sauté on low heat till the whole mixture comes together and oil starts appearing at the sides of the pan.
Add curd and half a cup of water; mix well to combine and cook covered for 2 minutes.
Remove the paneer from the water and add to the pan along with the bell peppers and roasted pepper fennel powder.
Season with salt and mix to combine taking care not to break the paneer pieces. Cook for another 5 minutes.
Finish off with dried mango powder and garnish with coriander leaves.
Serve warm with chappathis and raita.