Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a mixing bowl, cream together the butter, vegetable oil, and brown sugar for 2-3 minutes until fluffy.

Add the egg and vanilla extract and mix until well combined and smooth.

In a separate bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon. Gradually mix into wet ingredients until just combined.

In a new bowl, mix together softened butter, brown sugar, flour, cinnamon, and a pinch of salt until crumbly for the streusel topping.

Scoop generous portions of cookie dough onto the prepared baking sheet, spacing 2 inches apart and creating indentations with your thumb.

Fill the indentations with the prepared streusel mixture.

Bake cookies for 10-12 minutes until lightly golden around the edges and soft in the center.

While cookies cool, whisk together powdered sugar, milk, and vanilla extract for icing until smooth.

Once cooled, drizzle icing over each cookie and enjoy!