Preheat your oven to 400°F (200°C). Peel and dice the butternut squash into 4 to 5 cups of evenly sized cubes if this isn't already done. Line a large baking sheet with parchment paper to prevent sticking.

Melt the unsalted butter in a small bowl, ideally using the microwave in short bursts or in a saucepan over low heat. Add the packed brown sugar, ground cinnamon, salt, black pepper, and cayenne pepper (if using) to the melted butter. Stir until combined to form a flavorful butter mixture.

In a large bowl, toss the diced butternut squash cubes with about three-quarters of the butter and spice mixture until the pieces are well coated. Spread the squash out in a single layer on the prepared baking sheet. Roast in the preheated oven for 20 minutes.

After 20 minutes of roasting, take the baking sheet out and stir the squash pieces well to ensure even cooking. Meanwhile, in a separate bowl, combine the chopped pecans and dried cranberries with the remaining butter mixture, coating them evenly. I like to add a little extra brown sugar here if I want the pecans extra caramelized.

Add the coated pecans and cranberries to the baking sheet with the partially roasted squash, spreading them in a single layer to avoid clumping. Return the baking sheet to the oven and roast for an additional 10 minutes, stirring halfway through to prevent the pecans from overcooking. Remove from the oven and let cool slightly before serving.