Combine marinade ingredients in a small bowl and mix well
Place chicken in a larger bowl, cover completely with marinade, wrap and refrigerate
Thinly slice red onions and grate garlic and ginger into a paste
Brown onions on medium heat along with whole spices
Add garlic and ginger paste and sauté for 3 minutes
Add tomato paste and ground spices, sauté until fragrant
Add tinned tomatoes and cashews, simmer on low for 5 minutes
Remove whole spices and blend well, add water if needed
Return to low heat and add cream, sugar and butter
Place chicken thighs on an oven rack and broil at 220C for 10 minutes, flipping once, until lightly charred and cooked through
Chop cooked chicken and add to sauce
Knead roti dough well and let rest for 20 minutes
Roll thin, spread with melted ghee and flour, then laminate
Combine butter and water in a pot and heat until butter is melted
Combine dry ingredients in a large bowl and make a well in the centre
Pour wet ingredients over and bring together with a spatula
Let mixture cool before rolling into a pie crust
Line a tin with the crust and fill with butter chicken
Place roti over top, cut a steam vent and egg wash
Bake in a preheated oven at 200C for 40 minutes
