How to Make It
In a large bowl, mix the yogurt with the vindaloo spice and lemon juice. Add the chicken thighs and turn to coat. Cover with plastic wrap and refrigerate overnight.
In a large enameled cast-iron casserole, melt the butter over moderate heat. Add the onions, season with salt and pepper and cook, stirring occasionally, until golden brown, 12 to 15 minutes.
Add the chicken and its marinade along with the crushed tomatoes and stock to the casserole and bring to a simmer. Cook, stirring occasionally, until the sauce has thickened slightly, 20 minutes. Stir in the cream and simmer until the sauce is flavorful and the chicken is cooked through, 10 to 12 minutes longer. Season with salt and pepper and serve with basmati rice, cilantro sprigs and chopped cashews.