Chop the peeled butternut squash into cubes with sides of around 1.5 cm. Place in a baking tray, drizzle with sunflower oil and roast at 190°C (375°F) until they are soft enough to squash (ha-ha!) with a fork. This should take 35-40 minutes in a fan oven (convection); turn the pan every 10 minutes to stop the squash from burning.
When the squash has cooled, weigh 600 g (1 1/3 lbs) and blend it with the sugar, plain flour, maize flour, Armagnac, lemon juice, a few drops of vanilla essence and salt. Next, slowly add the water to obtain a puree that will fall off your spatula or spoon (the exact volume of water will vary with each squash and how well you roast it). Note: for a smooth, non-fibrous mixture, you may need to run your blender for around five minutes.
Spoon the mixture into muffin cases (I use a silicone tray with 12 cups, each holding 75 ml (2 1/2 oz); the quantities given in this recipe make enough mixture to fill them all nearly to the brim).
Bake in the oven for 40 minutes at 160°C (320°F). Turn the oven thermostat to 140°C (285°F) and bake for another 40 minutes.
Remove from the oven. When they have fully cooled, turn them out. Traditionally they are eaten cold, and this seems to accentuate their taste. They will keep for several days in an airtight container.