• Heat a dutch oven or large saucepan over medium-high heat. Add the olive oil, onions, garam masala, and salt. Stir to coat. Turn the heat down to medium and cover. Allow the onions to cook for 15-20 minutes, stirring occasionally, until they are soft and translucent and have reduced considerably.  
• Add the ginger, garlic, tomatoes, chili powder and crushed red pepper flakes. Cook, stirring occasionally, for 10 minutes, or until the tomatoes are almost completely incorporated into the onion mixture.
• Add the chicken and stir to coat. Cover and cook, stirring occasionally, for 5-10 minutes, or until the chicken is cooked through and the sauce has thickened.  If it's too dry, add boiling water 1/4 cup at a time to achieve a thinner consistency.
• Garnish with cilantro and serve with hot cooked jasmine rice and naan

For Garam Masala:

• Heat a large skillet over medium-high heat.  Add all whole spices (except ground cardamom). Toast until fragrant, but not burned.  
• Add all whole spices and ground cardamom to a spice or coffee grinder and pulse until all spices have been pulverized.
• Store in an airtight container.