Preheat the oven to 300 degrees F. Line 2 rimmed baking sheets with parchment paper.
Melt the butter in a small saucepan over low heat. Add the sugar, honey, vanilla, cinnamon and salt and stir to combine. Let cook until the sugar has dissolved, 1 to 2 minutes. Remove from the heat.
Combine the oats and almonds in a large bowl. Add the butter mixture and toss well to coat. Spread the mixture on the prepared baking sheets in a single layer.
Bake for 15 minutes, then stir in the raisins. Bake until crisp and golden brown all over, another 10 to 15 minutes. Transfer to a bowl. The granola will keep in an airtight container at room temperature for up to 2 weeks.
If you prefer the raisins to be less chewy, they can be added after the granola is fully cooked.