Add the olive oil and butter to a medium-sized saucepan over medium-high heat. When the butter starts to foam, add the chicken and cook for about 5 minutes until golden on all sides. Remove the chicken with a slotted spoon and set aside.
Add the spices and fresh ginger to the saucepan and cook for about 1 minute until fragrant. Add the garlic and cook for another minute.
Add the remaining ingredients, as well as the chicken pieces, turn the heat down to medium-low, and leave to simmer for about 15 minutes.
To make the cauli rice, roughly chop the cauliflower and add to a food processor. Pulse until you have rough, rice-like grains. Add the coconut milk to a saucepan, bring to a simmer and then add the cauliflower and cardamom. Cook for 3–4 minutes, drain off any excess liquid and season to taste.
Serve the butter chicken and cauli rice in warmed bowls topped with fresh coriander, slivered almonds and an extra drizzle of coconut milk.