In a medium mixing bowl, whisk together the flour, sugar, and cinnamon.
Pour in the melted butter and stir with a fork until moist clumps form. Set the bowl in the fridge while you make the dough.
Prepare the Cookie Dough Base
In a large bowl or stand mixer, beat the room-temperature butter, brown sugar, granulated sugar, cinnamon, vanilla, and salt on medium speed until smooth and creamy.
Add the eggs one at a time, mixing well after each addition.
Add the Dry Ingredients: Sift in the flour, cornstarch, baking powder, and baking soda. Mix on low speed until just combined. Stop mixing as soon as the flour disappears so the cookies stay tender.
Scoop, Roll, and Indent: Scoop out the cookie dough using a cookie scoop, then roll the dough into smooth balls using clean hands. Place them onto parchment-lined baking sheets.
Dip the back of a teaspoon into flour and press a shallow indent into the center of each dough ball.
Fill and Bake: Fill each indent generously with the crumble topping, pressing it gently into the dough so it sticks.
Bake at 180°C (350°F) for 10–12 minutes, until the edges are set and pale golden. Do not overbake; the centers will look soft but will set as they cool.
Cool and Glaze: Let the cookies rest on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.
Whisk the cream cheese, powdered sugar, vanilla, and salt in a small bowl until smooth. Drizzle over cooled cookies.
Notes
Weigh Ingredients in Grams: For consistent baking results, use a digital scale to weigh your flour, sugar, and butter.
Room Temperature Dairy: Ensure butter, eggs, and cream cheese are at room temperature so the dough and glaze emulsify cleanly without separating or clumping.
Do Not Overmix: Stop mixing as soon as the dry ingredients disappear to keep the cookies soft and tender. Overworking the dough creates tough cookies.
Press Crumble Securely: After making a shallow indent with a teaspoon, fill generously with streusel and press it gently into the dough so it stays in place while baking.
Avoid Overbaking: Remove the cookies from the oven when the edges are set and pale golden. The centers will look soft but will firm up on the warm sheet pan as they rest.
Cool Before Glazing: Let the cookies cool completely on a wire rack before drizzling with cream cheese glaze so the heat doesn't melt the glaze into a runny liquid.
Storage: Store cookies in an airtight container at room temperature for 3 to 4 days.