Preheat your oven to 350°F (175°C).

In a large bowl, mix the softened butter, vegetable oil, and brown sugar until fluffy, about 2-3 minutes.

Add the egg and vanilla extract, blending until smooth.

Gradually fold in the all-purpose flour, baking soda, baking powder, cinnamon, and salt to create a thick dough.

In a separate bowl, combine the softened butter, brown sugar, all-purpose flour, cinnamon, and a pinch of salt for the streusel.

Use your fingers or a fork to mix until crumbly.

Using a large cookie scoop, place dough balls on a lined baking sheet, spacing 2 inches apart. Make an indent in each and fill with streusel.

Bake for 10-12 minutes until golden brown around the edges. Cool for 10 minutes on baking sheet.

While cooling, mix powdered sugar, milk, and vanilla extract for icing until smooth.

Once cooled, drizzle icing over cookies.