Andhra Green Chili Chickpeas Curry with cilantro mint chili sauce

For the green sauce:

• 1/2 green chili, such as Serrano or Indian chili or use milder chilies or 1 tbsp green bell pepper
• 1 cup cilantro well-packed
• 1/2 cup mint leaves well-packed
• 1/2 cup water
• 1 teaspoon lemon juice
• 3 curry leaves fresh or frozen, optional

For the curry:

• 1 teaspoon oil
• 1/2 teaspoon cumin seeds
• 1 cinnamon stick
• 8 curry leaves , fresh or frozen or dried
• 1/2 green chili, Serrano or Indian, thinly sliced
• 1 cup chopped onion
• 2 tablespoons Ginger-Garlic Paste (or use 3 cloves garlic and 1/2 inch ginger, minced)
• 4 oz mushrooms quartered (I like to use white or cremini mushrooms)
• 1 tomato chopped into wedges
• 15 oz can of chickpeas drained or 1.5 cups cooked chickpeas
• 1 cup coconut milk or more, for creamier
• 1/2 teaspoon or more garam masala
• 1/2 teaspoon salt , more if needed

For garnish:

• cilantro, pepper flakes, lemon juice