Preheat oven to 325 F. Line a baking sheet with parchment paper or spray with oil.: As the oven warms you will notice a faint dry heat, and that steady warmth is what produces even toasting. Use parchment to prevent sticking and to make transferring easier. A common mistake is skipping the lining which can lead to burnt sticky bits, so take the extra minute. The sheet should feel evenly warm when you carefully hover your hand nearby.
Put oats in a large mixing bowl.: The dry rolled oats will look pale and slightly dusty, and they fill the bowl with a subtle oat scent. Using a large bowl gives you room to toss the mixture thoroughly. Avoid compacting the oats into a small bowl which can lead to uneven coating.
In a saucepan over low heat, melt coconut oil, Nutella, and honey together, stirring until smooth. Stir in salt. Pour this mixture over the oats and stir to coat the oats. Transfer to the prepared pan.: As the coconut oil melts, the Nutella will loosen and the honey will thin, creating a glossy syrup that smells of toasted chocolate and sugar. Stir constantly on low heat to prevent scorching, the mixture should become homogenous and pourable. Pouring it over the oats while warm helps each oat flake get a thin coating, which leads to crisp clusters. A frequent error is overheating which causes separation or a burnt aroma, so keep the flame low and watch for smoothness rather than bubbling.
Bake in preheated oven for 15 minutes. Stir in chopped hazelnuts. Return to oven and bake for another 15 minutes.: In the first bake the oats will start to dry and take on a light golden color, releasing a toasty, nutty scent. After the first 15 minutes stir to redistribute hot spots and add the hazelnuts so they toast without burning. The second bake deepens the color to a richer golden brown and creates crunchy clusters. Listen for a faint popping of nut oils and smell the sweet toasted aroma. Avoid skipping the stir, or some bits will overbrown.
Cool completely. Stir in chocolate chips.: Cooling is crucial because the granola sets as it drops to room temperature, forming those coveted clusters. As it cools, steam escapes and the mixture hardens slightly under your spoon, which is the right sign. Once cool, gently fold in the milk chocolate chips so they retain their shape. A common slip is mixing in chips while still warm, which melts them into the granola.
Store in airtight container.: Place the cooled granola into an airtight jar or container to preserve crunch and prevent moisture absorption. Stored properly it keeps its texture for days to weeks depending on humidity. One tip is to let it cool fully before sealing, otherwise trapped steam can soften the clusters. Check occasionally for any off smells indicating staleness.
