Preheat the oven to 200°C (180°C fan oven) Gas Mark 6. Spread the butternut squash on a baking tray, drizzle over the oil and some seasoning and bake for 18-25 minutes until tender. Leave to cool.
When the squash has cooled to room temperature, unroll the pastry, leaving the pastry paper underneath. Use a spatula to spread the ricotta over the top, then scatter over the squash, blue cheese and spinach.
Tightly roll up the pastry from one of the longest edges and put in the fridge or freezer to chill for 30 minutes. Preheat the oven to 200°C (180°C fan oven) Gas Mark 6 again.
Cut the pastry log into 8 even rounds, and arrange on a big baking sheet or in a roasting tin with about 3-4cm space between each round. Flatten each one with your hand so they look like squashed Chelsea buns. Bake for 20-30 minutes until golden brown and the filling melts together. Allow to cool for 5-10 minutes before enjoying for brunch, lunch or a picnic.