Position a rack in the center of your oven and another rack on the bottom. Preheat your oven to 325°F. Grease a 9" springform pan and line the bottom with parchment paper.

In a large bowl, combine butter and sugar. Cream together until pale and fluffy.

Add the milk and vanilla and beat until combined.

Add flour and salt and fold together until you have a sticky, streak-free cookie dough.

Portion out about ⅔ of the cookie dough and drop it into the bottom of your prepared springform pan. Spread into an even layer.

Bake the cookie crust for 20-25 minutes or until golden brown. Set the crust aside to cool slightly.

To the remaining ⅓ of the cookie dough, add the sprinkles and mix to combine. Roll into bite-sized balls and set aside.

In a large bowl, combine cream cheese and sugar. Cream together until lump free.

Add in the flour, yogurt, salt, and vanilla. Beat together until combined.

Mix the eggs into the batter one at a time, mixing just until combined. Avoid overmixing.

Pour about ⅓ of the cheesecake batter over the slightly cooled cookie crust.

Drop about half of the cookie dough balls evenly on top. Layer another ⅓ of the cheesecake batter, then drop the remaining cookie dough balls on top, and pour the remaining cheesecake batter.

Bake the cheesecake with a pan of boiling water on the bottom rack for 1 hour 10 to 1 hour 20 minutes until firm.

Cool the cheesecake in the oven with the door slightly ajar for 1 hour total, then let cool on the counter and refrigerate.

Heat treat the flour to make it safe to eat. Let the flour cool to room temperature then sift.

In a bowl, whip the butter until lump free. Mix in powdered sugar until combined.

Add cooled flour, salt, vanilla, and milk to achieve desired consistency, then fold in jimmies sprinkles.

Spread frosting on top of cooled cheesecake and decorate with assorted sprinkles if desired.