When the half of squash is slightly cooled, scoop out, and puree in a food processor until smooth. Add a tablespoon or two of stock to thin if needed. Set aside.
Add about 1/4 - 1/2 cup of warm stock at a time and stir until fully absorbed. Repeat the process, seasoning throughout with salt, until almost all of the liquid is added and absorbed (will take about 20 mins).
Stir in the nutmeg, parmesan, butter, and thyme until incorporated.
Fold in half of each of the roasted diced squash, apples, and pancetta.
Spoon into bowls and serve immediately. Garnish with the reserved squash chunks, apples, pancetta, and minced thyme.