Using a mixer, cream together the butter, 1 1/4 cups sugar and the 1/4 cup of brown sugar. Add in the eggs one at a time and mix after egg is added. Then add the vanilla extract and mix until combined.
In a different medium bowl, mix together the flour, baking powder, salt and 1 tsp cinnamon.
Gradually add the dry ingredients to the wet mixture and mix until combined.
To make it easier to roll the dough into balls, cover the bowl with plastic wrap and place in the refrigerator for 15-30 minutes.
Make the cinnamon sugar topping by combining the 4 Tablespoons sugar and 1 1/2 teaspoons cinnamon in a small bowl.
Roll the dough into 1-inch balls. Then roll the balls in the cinnamon sugar mixture and place them on a cookie sheet that has been prepared with parchment paper. Bake cookies at 350 degrees for 8-10 minutes.
Place the Snickerdoodles on a cooling rack to cool completely.