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. Using an electric mixer fitted with the paddle attachment or a wooden spoon by hand, 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 in the center of your preheated oven for 20-25 minutes or until the surface is no longer shiny and the edges are lightly golden brown.

Set the crust aside to cool slightly (but keep the oven preheated to 325°F).

Line a baking sheet or large plate with parchment paper. To the remaining ⅓ of the cookie dough, add in the sprinkles and mix to combine. Scoop out little bite sized pieces of dough that are about ½ a teaspoon and roll into balls. Place onto your parchment lined baking sheet or plate and repeat until all of the sprinkle dough is portioned into bite sized pieces. Set aside.

In a large bowl, combine cream cheese and sugar. Using an electric or stand mixer, or wooden spoon by hand, cream together until lump free.

Scrape down the bottom and sides of your bowl, then add in the flour, yogurt, salt, and vanilla. Beat together until combined.

If using a mixer, make sure to do this next step on LOW speed to avoid incorporating too much air into the cheesecake batter. Mix the eggs into the batter, one at a time, mixing just until the egg disappears before adding in the next one. After adding 2 of the eggs, pause to scrape down the bottom and sides of the bowl before continuing. Take care not to overmix.

Pour about ⅓ of the cheesecake batter over the slightly cooled cookie crust (it's OK if it's still a little warm).

Drop about half of the cookie dough balls evenly on top. Layer another ⅓ of the cheesecake batter on top to cover the cookie dough then evenly drop the remaining cookie dough balls on top. Pour the remaining cheesecake batter on top and spread into an even layer.

Fill a separate large baking pan with about 2 inches of boiling water and carefully position it on the bottom rack of your oven. Place the cheesecake on the center rack of your oven above the pan filled with water.

Bake the cheesecake in your preheated oven for 1 hour 10 minutes to 1 hour 20 minutes or until it's puffed up and golden brown around the edges. If you gently shake the pan, the center of the cheesecake should wiggle but the edges should be firm.

Because of the moisture in the cookie dough, this cheesecake will crack - that's completely normal!

Turn the oven off and crack the door open slightly. Cool the cheesecake for about 30 minutes in the oven with the door slightly ajar. After 30 minutes, run a pairing knife around the edges of the cheesecake to make sure it's not stuck to the sides of the pan (this helps prevent tearing as the cheesecake cools and shrinks).

Continue cooling the cheesecake for an additional 30 minutes in the oven with the door slightly ajar (for a total of 1 hour cooling in the oven). Take the cheesecake out and let it cool on your counter until it reaches room temperature, then pop it into the fridge and let it chill for at least 6 hours or until firmed up.

Heat treat the flour to make it safe to eat: Preheat your oven to 350°F and line a medium baking sheet with parchment paper. Sprinkle the flour onto the baking sheet in an even layer. Bake in the center of your preheated oven for 5 to 7 minutes or until the flour reaches a temperature of 160°F.

Let the flour cool completely to room temperature then sift it to work out any clumps. Set aside.

Add butter into a large bowl. Using an electric mixer fitted with the paddle attachment or a wooden spoon by hand, whip until lump free.

Mix powdered sugar into the butter, 1 cup at a time, until combined. Mix in the cooled flour to combine.

Add the salt, vanilla, and 1 tablespoon of milk and whip until light and fluffy. If the frosting is too thick, mix in a splash more milk to thin it out to your desired consistency.

Lastly, fold the jimmies sprinkles into the frosting.

Unlatch the sides of the springform pan and move the cheesecake onto your serving plate or cake stand. Spread the frosting on top and decorate with assorted sprinkles if desired. Serve right away or keep in the fridge until ready to serve!