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

In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and ground cinnamon.

Gradually add the dry ingredients to the wet mixture, mixing until just combined. Be careful not to overmix.

If using nuts, fold them into the dough at this stage.

Use a cookie scoop or tablespoon to drop rounded dough onto the prepared baking sheets, leaving space between each cookie.

For the streusel topping, mix a bit of flour, sugar, butter, and cinnamon together in a small bowl until crumbly, then sprinkle it over the cookie dough.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden.

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

Drizzle with powdered sugar mixed with a little water or milk for a light icing if desired.