Preparation

• Prepare the streusel filling: In a medium sized bowl combine the flour, brown sugar, cinnamon and salt together. Then work in the butter until small clumps form. Refrigerate.
• Preheat the oven to 400°F. Line two baking sheets with parchment paper or silicone baking mats. Set aside.
• Combine the dry ingredients in a large bowl: all purpose flour, cake flour, corn starch, cinnamon, baking soda, baking powder and salt. Set aside.
• Place the cubed butter and sugars into the bowl of a stand mixer and secure the paddle attachment. Turn the mixer on and cream until smooth, about 1-2 minutes.
• Add in the egg, egg yolk and vanilla extract and blend until mixed. Use a rubber spatula to knock off mixture if any is sticking to the sides of the bowl and mix again.
• Gradually add in the dry ingredients, about ¼ cup at a time. Mix until incorporated.
• Scoop and roll cookie dough into ~8 large balls, or smaller if preferred (you can get about 22-24 cookies). Place on prepared baking sheets.
• Make an indent in each cookie, using your thumb or the end of a spoon/spatula or something similar.
• Spoon ~1 Tbsp. of the streusel filling in each cookie and bake for ~8-11 minutes, or until edges appear set and are slightly golden.
• *Optional step to get cookies perfectly circular: Immediately after the cookies come out of the oven, place a circular cookie cutter or a circular drinking glass around one of the cookies and give the cookies a spin.
• Let cookies rest on cookie sheet for ~5 minutes then transfer to a cooling rack.
• Whisk together the ingredients for the icing and once the cookies are cooled, drizzle icing over the tops and enjoy!