Preheat the oven to 350 degrees Fahrenheit. Line a muffin pan with paper liners and set aside.
In a measuring cup, whisk together Greek yogurt and milk; set aside.
In a medium bowl, whisk together the flour, cinnamon, baking powder, baking soda and salt.
In the bowl of an electric mixer fitted with the paddle attachment, beat butter and sugar on medium-high speed until light and fluffy, about 3 minutes. Beat in eggs and vanilla. On low speed, alternate adding dry ingredients and yogurt/milk in three additions, beginning and ending with the dry ingredients. Beat just until incorporated.
Divide the batter evenly between the prepared cupcake liners, filling each about 2/3 full.
Bake for 18 to 20 minutes, or until a toothpick inserted into the center comes out clean. Allow to cool 5 minutes, then transfer to a wire rack to cool completely.