Melt the butter and allow it to cool slightly. If the pumpkin purée looks watery, spread it between paper towels and gently blot away excess moisture.

Whisk the flour, baking soda, salt, cinnamon, nutmeg, and cloves together in a medium bowl.

In a large bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth. Add the egg yolk, vanilla, and pumpkin purée, whisking until evenly combined.

Gradually add the dry ingredients to the pumpkin mixture and stir only until no obvious streaks of flour remain. Fold in the semisweet chocolate chips.

Cover the dough and chill it for about 30 minutes. This firms the melted butter, reduces spreading, and helps the finished cookies retain a soft, chewy texture.

Preheat the oven to 350°F (177°C) and line baking sheets with parchment paper. Scoop rounded tablespoons or approximately 3-tablespoon portions of dough onto the sheets, leaving room between portions.

Bake for 12–13 minutes, until the edges look set while the centers still appear slightly soft. Avoid waiting for the centers to look completely firm in the oven.

Let the cookies cool on the baking sheet for several minutes, then transfer them to a wire rack. Repeat with the remaining dough until all the cookies are baked.