Preheat the oven to 350°F (175°C) and prepare a large baking sheet by lining it with parchment paper. This ensures even baking and easy removal of the cookies later.

In a medium mixing bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon until evenly combined. This step helps to evenly distribute the leavening agents and spices throughout the dough. Set the dry mixture aside.

In a separate large bowl, whisk or beat together the melted butter, brown sugar, and granulated sugar until the mixture turns light in color and thickens slightly, about 3 minutes. The texture should resemble a smooth caramel paste. Add the vanilla extract and egg, then mix until fully incorporated and glossy.

Gradually add the dry ingredients into the wet mixture, stirring gently until no streaks of flour remain. Avoid overmixing to keep the cookies soft and chewy.

Fold in the chocolate chips, butterscotch chips, and chopped pecans using a rubber spatula, making sure the mix-ins are evenly distributed. The dough should be slightly sticky but easy to handle.

Using a standard cookie scoop or two tablespoons, portion the dough onto the prepared baking sheet, spacing each mound about 2–3 inches apart to allow for spreading.

Bake the cookies in the preheated oven for 10–12 minutes, or until the edges are lightly golden while the centers remain pale and puffy. The cookies will continue to bake from residual heat once removed from the oven, so a slightly underbaked appearance is ideal for a soft, chewy texture.

Immediately sprinkle each cookie with a light dusting of flaky sea salt to balance the sweetness and enhance the butterscotch flavor. Allow them to cool on the baking sheet for 5 minutes before transferring to a wire rack to finish cooling.

Once cooled slightly, the cookies are ready to enjoy — crisp-edged, gooey-centered, and irresistibly rich with the flavors of butterscotch, chocolate, and toasted pecans.