Combine coriander seeds, cumin seeds, peppercorns, fenugreek seeds, curry leaves, green chilies and ginger in a mortar. Pound with the pestle until a coarse paste forms.
Heat 2tbsp ghee or oil in a medium sauce pan; add the pounded mixture and stir-fry to cook the spices without burning them, about 30 seconds. Add the kidney beans and green peas, mix well with the spices.
Pour 1 cup of water and sprinkle the salt. Bring the mixture to a boil. Lower the heat and boil, uncovered, stirring occasionally, about 5 minutes.
Combine the yogurt and cream in a small bowl and whisk them together. The fat in cream stabilizes yogurt and prevents it from curdling. Pour this mixture into the saucepan and continue to boil the curry, uncovered, stirring occasionally, until the kidney beans and green peas are tender, about 8-10 minutes.
Whisk rice flour (cornstarch or besan) in 2tbsp of cold water, making sure that there are no lumps. Pour this into the curry and mix well, curry with thicken instantly, cook for 2 minutes and serve.