Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Brush the cut sides of the honeynut squash halves with olive oil and sprinkle with a pinch of salt. Place them cut-side down on the prepared baking sheet.

Roast for 25-35 minutes, or until fork-tender. Let cool slightly. Scoop out the flesh into a bowl and mash thoroughly with a fork or potato masher until smooth. You'll need 1/2 cup of puree for the cookies; reserve any extra for another use. Allow the puree to cool completely before using.

In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, ground cinnamon, and salt. Set aside.

In a large mixing bowl, using an electric mixer, cream together the softened butter, granulated sugar, and light brown sugar on medium speed until light and fluffy (about 2-3 minutes).

Beat in the large egg and vanilla extract until well combined. Scrape down the sides of the bowl as needed.

Add the cooled honeynut puree to the wet ingredients and mix on low speed until fully incorporated.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix the dough.

Cover the bowl with plastic wrap and chill the cookie dough in the refrigerator for at least 30 minutes (or up to 2 hours). Chilling helps prevent spreading and deepens flavor.

Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.

Scoop rounded tablespoons of cookie dough (about 1.5-2 tbsp per cookie) and place them about 2 inches apart on the prepared baking sheets.

Bake for 10-12 minutes, or until the edges are lightly golden and the centers are set. The cookies might look slightly underdone in the middle, but they will firm up as they cool.

Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

Once cookies are completely cool, place white chocolate chips in a microwave-safe bowl. Microwave in 30-second intervals, stirring well after each, until smooth and melted. Be careful not to overheat.

Stir in the chopped pistachios and optional green food coloring until evenly distributed. If the chocolate thickens too much, microwave for another 10-15 seconds.

Drizzle the pistachio chocolate over the cooled cookies using a spoon or fork, or dip half of each cookie into the chocolate. Place them back on the wire rack (over parchment paper to catch drips) and let the chocolate set.

Allow the chocolate to fully harden at room temperature or by refrigerating for 10-15 minutes.