Heat oven to 400°F.
Quarter and seed squash; Brush squash pieces with olive oil and place cut side down on rimmed baking sheet.
Pour 1/4 cup water over baking sheet and cover tightly with foil.
Roast 40 - 45 minutes or until squash is tender and mashes easily with a fork. Scoop mashed squash out of its skin and set aside.
Bring large pot of salted water to boil. Cook pasta to al dente. Drain and set aside.
Melt butter in large saucepan over medium heat. Whisk in flour, adding pinch of sea salt and pinch of pepper. Reduce heat to medium-low. Whisk in half and half, 1 tablespoon at a time.
Stir until mixture has thickened; whisk in beer and cheddar until smooth and creamy. Fold in 1 cup mashed squash.
Mix in reserved pasta and adjust salt to taste. Finish with a few sage strips and pinch of freshly ground white pepper.