Twice-baked squash soufflés with fontina and spinach sauce

By Theo Randall From Saturday Kitchen Ingredients For the soufflés 400g/14oz butternut squash, peeled, seeds removed olive oil, for drizzling 45g/1¾oz unsalted butter, plus extra for greasing 45g/1¾oz plain flour, plus extra for dusting 500ml/18fl oz hot full-fat milk 250g/9oz …