In a small bowl, mix the cinnamon-sugar coating ingredients together. Set the bowl aside.
In a medium-sized bowl, sift together the flour, cornstarch, cream of tartar, baking soda, cinnamon, and salt. Set aside.
In a mixing bowl, cream together the softened butter and sugars with a handheld mixer. Once it’s well incorporated, add
the eggs. After the eggs are mixed in, add the cookie butter and vanilla extract. Add the flour mixture gradually to the
sugar mixture on a slow speed. Mix until just incorporated. Do not overmix. Using a 1 1/2 inch wide cookie scoop, place
dough balls into the cinnamon sugar bowl and roll them so the ball is covered in sugar. Then place each ball on parchment
paper or a silicon mat on top of a baking pan. Place in the refrigerator for 20-30 minutes while the oven preheats. Preheat
the oven to 350 degrees Fahrenheit while the dough is chilling. Bake the cookies for about 10-12 minutes on the middle
oven rack. Once they have cooled for about 3-5 minutes, remove the cookies from the pan and place them on a cooling
rack. While the cookies are cooling off, melt your cookie butter in the microwave for a few seconds until melted. Do the
same with the white chocolate chips, adding a tablespoon or so of oil to the white chocolate chips. Melt the chips for a few
seconds at a time in the microwave. Then, drizzle the tops of the cookies with melted cookie butter and/or melted white
chocolate mixtures as desired. Sprinkle crushed Biscoff cookies on top.