Heat oil in a pan. Add cumin seeds, bay leaf, cloves, cinnamon, cardamom , whole black pepper.
Add slit green chilies and chopped green onions. Saute till onions turn translucent.
Add chopped red and green capsicum. Add some salt.
Saute till the capsicum soften. Add ginger garlic paste. Saute.
Add the coarsely crushed tomatoes. Cook till tomatoes soften and becomes mushy.
Add spices - turmeric powder, red chili powder, coriander cumin powder, biryani powder, garam masala and salt.
Mix well and saute till the spices are nicely absorbed.
Add the marinated mushrooms and paneer along with the yogurt mixture.
Mix well gently.
Cover and cook the mixture on low to medium heat till the mushrooms soften for about 5-7 minutes.
Add kasuri methi (crushed between palms), mint powder or fresh mint leaves (around 1/4 cup).
Mix well and simmer. The oil will float on top. The gravy is ready. Keep aside and use for assembling the biryani.