This garam masala spice blend is flavourful and complex. But don't worry if you are missing a few of the spices. Just try to include as many as possible or try one of the garam masala substitutes instead.
Heat a conventional oven to 160 °F. Spread everything apart from the poppy seeds and rose petals on a baking sheet. Place the baking tray in the oven for 2 ½ hours.
Add the poppy seeds and rose petals to the tray, place it back in the oven and turn the oven off. Allow the mixture to cool in the switched-off oven for 30 minutes.
Transfer the cooled spice mix to a spice grinder (or coffee grinder) and blitz it into a fine powder.
Stovetop method:
Put everything apart from the poppy seeds and rose petals into a cold, dry frying pan or skillet and place over medium-high heat. Toast the spices for 3 minutes, shaking the pan occasionally.
Remove the pan from the heat and add the poppy seeds and rose petals. Let the mixture cool in the pan.
Transfer the cooled spice mix to a spice grinder (or coffee grinder) and blitz it into a fine powder.
Notes
Lower the temperature if you have a fan oven. I suggest 120 °F (50 °C) but check on the spices every 30 minutes to ensure they are getting sufficient heat without burning.
While the spice mix won't go off anytime soon, spices start to lose their intensity as soon as you grind them. So, for the best flavour, aim to use homemade spice blends within 30 days.