Testing - Creamy Squash, Blue Cheese, and Walnut Pasta

1 - I altered the recipe before even trying it! But it was good, and requires some tweaking. I did not use the walnuts which was a mistake - it needs it. I also want to add some sage to add what we feel is a missing flavour. Oh, and I didn't get the bit about adding flour to the egg yolk, so I'll be adding it in the previous step to get it to brown and absorb flavour, first.
2 - The changes I made worked very nicely, but there is still something missing. I'm adding some sage and a little more cheese.

4 cups (1/2-inch) cubed peeled butternut  (I used Turban) winter squash (about 1 1/3lbs)
2 + 1 tsp olive oil
1/4 + 1/4tsp salt
1/4 +1/4 tsp freshly ground black pepper, divided
8 oz uncooked chunky pasta
1 small onion, chopped
2 cloves garlic, minced
1 Tbsp flour
2 tsps minced fresh sage
1/2 + 1/2 cup milk, divided
2 large egg yolks
3 2 oz Cambozola blue cheese, crumbled (about 1/2 cup)
3 Tbsp chopped walnuts, toasted

1. Preheat oven to 425 F.
2. Toast the walnuts and set aside.
3. Combine squash, 2 teaspoons oil, 1/4 teaspoon salt, and 1/4 teaspoon pepper on baking sheet. Bake for 30 minutes or until tender, stirring once.
4. Cook the pasta until al dente. Drain pasta; keep warm.
5. Heat the remaining teaspoon of oil in a pan and sauté onion and garlic until just starting to soften. Add the flour and sage. Mix until the flour covers the onion and garlic.
6. Reduce the heat and continue to sauté for a few minutes, allowing the pan to cool a bit before stirring in 1/2 cup milk, the remaining 1/4 teaspoons of salt and pepper. Remove the pan from the heat source.
7. In a small bowl whisk together the remaining 1/2 cup of milk, the flour and the yolks. Slowly add the egg mixture to the pan, stirring constantly with a whisk. Add the cheese and cook 5 minutes or until thickened, stirring frequently.
8. Combine the squash, pasta, and sauce; toss gently to coat. 
9. Before serving, sprinkle with cheese and the toasted walnuts.