Preheat and prepare. Heat your oven to 300°F and line a large baking sheet (or two smaller ones) with parchment paper or a silicone mat. A prepared baking sheet ensures nothing sticks and makes cleanup easy.

Mix the dry ingredients. In a large mixing bowl, combine oats, crunchy pecans, pepitas, and additional ingredients if you wish. Stir in cinnamon, nutmeg, ginger, cloves, salt, and brown sugar until the dry ingredients are well coated with the warm spices.

In a separate bowl, whisk together pumpkin purée, sourdough starter, pure maple syrup, and vanilla extract. Whisk until the pumpkin mixture is smooth and glossy.

Combine. Pour the wet ingredients over the dry ingredients. Using a wooden spoon or spatula, stir until everything is evenly coated. The oats and nuts should look slightly damp and clump together — that’s how you know you’ll get big clusters instead of loose, unbaked granola.

Spread it out. Transfer the granola mixture onto your prepared sheet pan. Spread into an even layer but keep it slightly pressed together. Don’t spread it too thin — pressing helps create those big clusters.

Bake. Bake for 40 minutes, then carefully stir, flipping the clusters over. Rotate your pan and return it to the oven. Continue baking for another 15–20 minutes, checking at the 15-minute mark. The granola should look golden brown and smell like fall goodies.

Cool completely. Let the granola cool on the baking sheet without touching it. As the granola cools, it firms up and forms crunchy clusters. If you stir too soon, you’ll break them apart. Wait until the granola cools completely before transferring it to an airtight container such as a wide mouth mason jar.

Add extras. Once cooled, stir in dried cranberries, chocolate chips, or coconut flakes if desired.