1. Par-Bake Squash: Drizzle a little olive oil over the prepared squash - rub the oil
in well to coat the skin and insides. Sprinkle over with a little salt. Bake in a preheated 350°F oven until they have softened and are beginning to color, 30-40 minutes.
2. Prepare Spinach: While
the squash is cooking, boil the spinach until soft and strain
immediately. Allow to cool and then press the spinach to remove any
excess water. They need to be as dry as possible. Shred the spinach
roughly and set to one side.
3. Make the sauce: In a medium saucepan, heat the butter over
medium-low heat until melted. Add the flour and stir until smooth. Over
medium heat, allow to cook for 1 minutes, but not to the point of coloring. Slowly whisk in the hot milk and continue to whisk
until the sauce thickens and comes to a boil, about 2 to 3 minutes.
Reduce the heat to a simmer and season with the salt, pepper and
nutmeg. Allow to simmer for 2 to 3 minutes. This is now called a Béchamel sauce, and may be used as is to top any number of dishes. Stir in the cheese and whisk until melted - this now a Mornay sauce. Take the sauce off the heat.
4. Fill Squash: The béchamel sauce needs to be
thick to hold the spinach and not spill out of the squash. Mix spinach into sauce and spoon into the par-cooked squash and return to the oven to finish cooking and set the filling, about 30 minutes.
