Heat the oil in a large pot over low-medium heat. Once hot, add the onion and cook for 8-10 minutes, until translucent and lightly browned. If it's browning too much, reduce the heat.
1 tablespoon olive oil, 1 medium onion
Add the garlic and ginger and cook for another couple of minutes, until fragrant.
2 cloves garlic, 1 tablespoon minced ginger
Stir in the spices and cook for another 30 seconds or so. Add 2 tablespoons of water to deglaze and lift anything that might be sticking to the bottom of the pot.
Take half of the mixture and blend it in a food processor (see note) with 2 tablespoons water until smooth. Add back to the pot and mix very well to combine. This is what holds the burgers together.
Preheat the oven to 190°C (375°F) and line a large baking sheet with parchment paper. Lightly oil the paper with a little extra olive oil and set aside.
Form the mixture into six large burgers, about 2-2.5cm (~1 in.) thick and place onto the prepared baking sheet. Bake for 30 minutes, carefully flipping the burgers after 15 minutes and returning to the oven.
Serve hot with desired toppings. Leftovers will keep for a couple of days in the refrigerator.
Notes
If you don't have a food processor, a potato masher will do the trick. Still aim to mash about half the mixture, referring to the above image (step 6 in the pictures) for the right texture.Nutrition is calculated for this recipe for the burger only, without any possible topping or bun you might choose to include.