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

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

Add the eggs one at a time, beating well after each. Mix in the vanilla extract.

In another bowl, whisk together the flour, baking powder, baking soda, and salt. Gradually add to the creamed mixture, alternating with the sour cream. Start and finish with flour mixture.

Fold in mini chocolate chips if using.

In a small bowl, mix the crumble topping: combine flour, brown sugar, and cinnamon, then stir in melted butter until crumbly.

Scoop cookie dough onto prepared sheets, spacing 2 inches apart, and flatten slightly. Generously sprinkle crumble topping on each.

Bake for 12-15 minutes or until edges are golden brown.

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