1. Cut the squash in half lengthwise. Scoop out the seeds and place the squash halves inside-down on a baking sheet. Bake at 350 for one hour, or until tender.
2. Separate the squash strands with a fork and place in a bowl. Discard shells. Leave the oven on.
3. In a large saucepan, melt butter over medium heat. Add flour and stir. Reduce heat to low and cook, stirring continuously, for 5 minutes.
4. Dissolve bouillon cubes in hot water. Stir into flour mixture. Add the milk slowly and whisk to combine. Cook the sauce, stirring continually, until thickened (about 10 minutes). Add in 1/2 cup parmesan, salt and pepper.
5. Add squash to the sauce and mix well. Spoon the mixture into a 3-quart baking dish. Sprinkle the remaining parmesan on top.
6. Bake about 30 minutes at 350, or until bubbly and golden on top.