To Make the Peanut Butter Cookie Crust:

1. Preheat oven to 325°F.
2. In a large bowl, combine creamy peanut butter, sugar, and eggs with a spoon or spatula until blended.
3. Press into the bottom of a well-greased 8-inch springform pan.
4. Bake for 30-35 minutes, or until edges are golden brown, and a toothpick inserted near the center comes out clean.
5. Cool in pan on a wire rack for 15 minutes before releasing the sides of the springform pan. Cool completely.
6. Run a knife around the bottom edge of the cookie crust to loosen, and transfer it to a serving platter.

For the Toppings:

Make the Peanut Butter Sauce:

1. In a small microwave-safe bowl, heat the peanut butter for 30-45 seconds, or until thin and runny.
2. Spread the melted peanut butter over the cookie crust in an even layer, to within 1 inch of the edges.
3. Place in the refrigerator for 10-15 minutes to allow the peanut butter to chill and to set.

Make the Chocolate Ganache:

1. Meanwhile, in a medium microwave-safe bowl, combine milk chocolate chips, heavy whipping cream, and butter.
2. Heat on high for 1-2 minutes, or until heavy cream begins to boil.
3. Whisk until chocolate chips are completely melted and the mixture is smooth.
4. Place in the refrigerator for 10-15 minutes to allow the ganache to slightly thicken.

To Serve:

1. Once the peanut butter layer on the cookie crust is set, and the ganache is slightly thickened, spread the ganache over the peanut butter layer in an even layer.
2. Immediately sprinkle with M&Ms and peanut butter chips.
3. Allow 30 minutes to set. Cut and serve!