• PREHEAT the oven to 400°F (225°C). Place the oven rack in the center position. (See Note #1.)
• LINE a baking sheet with parchment paper or a silicone mat.
• SIFT several (4-5) cups of flour back and forth between 2 large bowls 3 to 4 times. Use a flour sifter or a wire mesh strainer.
• WEIGH  396 grams of the sifted flour on a digital kitchen scale and place it in a medium bowl. (See Note #2.)

  If you don't have a scale, use 3 cups + 1 tablespoon of flour. (To measure, spoon the flour into a measuring cup and use the back of a knife to level it.)
• WHISK the baking powder and salt into the flour.
• In a separate bowl, CREAM 1⅔ cup (330 grams) of sugar and the butter together with an electric mixer on high speed for 1½ to 3 minutes, or until the texture progresses from sandy to creamy. 

  Please note: The butter should be between 62 to 65°F (16 to 20°C). Colder butter could prevent the cookie from spreading enough as it cooks. Warmer butter will cause the cookie to spread too much when baking and may create a more crispy cookie. If the butter gets too warm, refrigerate it for a few minutes before creaming it.
• BLEND the vanilla and eggs into the creamed sugar and mix on medium speed for 15 to 20 seconds.

  Please note: Take the eggs straight from the refrigerator before blending. They should be cold. (See Note #3.)
• MIX the dry ingredients into the wet ingredients. Use an electric mixer on low speed and mix until the flour is thoroughly mixed in. Scrape the sides and bottom of the bowl to get all the flour.
• In a small, shallow bowl STIR the cinnamon with 3 tablespoons (38 grams) of sugar until blended.
• SCOOP the cookie dough with a 2-tablespoon cookie scoop. (See Note #4 for instructions on using a smaller scoop.)
• ROLL the cookie dough ball in the cinnamon-sugar mixture until it is thoroughly coated.
• PLACE the cookie dough ball on the lined cookie sheet.
• REPEAT rolling the cookie dough balls and place them all on the baking sheet 2 to 3 inches apart.
• BAKE for 8 to 10 minutes. If your oven heats unevenly, rotate the cookie sheet in the oven at the 6-minute mark so the cookies bake evenly. Then bake an additional 1 to 3 minutes, or until the edges are set, but middle does not look completely done. Use your judgement here. The cookie should not be doughy. Bake until the cookies look almost done.
• REMOVE the baking sheet from the oven and cool the pan on a cooling rack for 5 minutes. Turn the oven off.
• TRANSFER the cookies from the baking sheet to the cooling rack and allow them to cool completely, about 45 minutes to 1 hour.
• REST the cookies. Place the cooled cookies in an airtight container for a minimum of 1 hour, but 2 to 3 hours is better. (See Note #5.)

  (A better option is to freeze them overnight. See instructions below.)
• SERVE with hot chocolate or a glass of cold milk.

TO FREEZE & THEN THAW (for amazing taste):

• COOL the cookies completely.
• STACK the snickerdoodles 3 or 4 cookies high.
• DOUBLE WRAP the stacked cookies with plastic wrap, ensuring that the cookies are completely covered.
• PLACE the wrapped cookies in an airtight freezer container.
• FREEZE the cookies for at least 24 hours. But a few days is fine.
• REMOVE the cookies from the freezer several hours before eating them.
• BRING the cookies to room temperature.
• UNWRAP the cookies and place them on a serving plate.
• EAT AND ENJOY!