Step 1: Make the Dough
In the bowl of a stand mixer, fitted with the paddle attachment, beat butter, granulated sugar, and brown sugar on medium speed until light and fluffy (about 2 minutes).
Add the egg, egg yolk, and vanilla extract, mixing until combined.
In a medium bowl, whisk together the flour, cinnamon, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until a soft dough forms.
Step 2: Roll and Cut the Cookies
Roll the cookie dough out on a piece of parchment paper to about 1/4-inch thickness. If the dough is sticky, dust it with a little flour.
Using a rolling pin, roll out the dough evenly.
With a sharp knife or large cookie cutter, slice the dough into small size squares (about 1/2 inch to 3/4 inch). If you want to purchase animals shapes cookie cutters you can grab them here.
Transfer them to a prepared baking sheet lined with sheets of parchment paper.
Step 3: Bake the Cookies
Bake at 350°F for 9-10 minutes, or until the edges turn golden brown. Keep an eye on them at the minute mark to avoid overbaking.
Remove from the oven and let them cool completely on a cookie sheet before frosting.
Step 4: Make the Dippable Frosting
In a medium bowl, whisk together powdered sugar, melted butter, vanilla extract, milk, and meringue powder until smooth. The consistency should be thick but still dippable. Add more milk if needed.
Divide the frosting into two bowls. Leave one white and tint the other pink with natural food coloring or red food coloring.
Step 5: Dip & Decorate the Cookies
Dip the top of each cookie into the frosting, letting any excess drip off.
Place the cookies on a piece of parchment paper and immediately top with rainbow sprinkles or nonpareil sprinkles.
Let the frosting set for about 30 minutes, or until dry to the touch.