Kabocha Squash Focaccia with Gruyere, Caramelized Onion & Sage – These are the Days

Ingredients

• 1 ¼-oz. envelope active dry yeast (about 2¼ tsp.)
• 2 tsp. honey
• 5 cups (625 g) hard red wheat flour (see note below)
• 1 tablespoon pink Himalayan salt
• 6 Tbsp. extra-virgin olive oil, divided, plus more for hands
• 4 Tbsp. unsalted butter, divided
• 1 medium onion
• 1 kabocha squash
• 4 oz gruyere, coarsely grated
• 12-18 sage leaves
• Flaky sea salt