- Preheat the oven to 190°C.
- Cream the butter, brown sugar and granulated sugar together in the bowl of a stand mixer fit with the paddle attachment for 3 minutes on medium-high speed. Add the egg and the yoghurt, and continue mixing for another 2 minutes.
- Sift the flour, salt, baking soda and baking powder together in a separate bowl. With the mixer set on low, slowly add the flour mixture into the butter mixture about 1/2 cup at a time, letting each pour of flour incorporate fully before adding the next.
- Roll the dough into 1-inch balls and set them 2-inches apart on an ungreased cookie sheet. Bake the brown sugar cookies for 10 to 12 minutes until they’re golden brown around the edges, and then remove the cookie sheets from the oven. Allow the cookies to rest for a minute before removing them to wire racks to cool completely.