Preheat the oven to 350 degrees F. Spray a mini muffin tin with non-stick cooking spray. Set aside.

In a large bowl, using a hand-held mixer or stand mixer with a paddle attachment, cream butter. Add both sugars and continue beating until light and fluffy. Mix in eggs, one at a time, mixing well after each addition and scraping the sides of the bowl as needed. Add vanilla extract and mix well.

In a separate bowl, stir together the flour, pudding mix, baking soda and salt. Slowly add the flour mixture, a little at a time, to the butter mixture, mixing just until combined. Add M&M's® Easter Sundae chocolate candies and beat a few times, until M&M's® are fully incorporated (it is okay if the M&M's® break up during mixing).

Using a small cookie scoop, drop dough by rounded tablespoonfuls into prepared mini muffin pan. Bake in a preheated 350 degree oven for 12-14 minutes, or until golden brown and set in the middle. Remove muffin tin from oven and gently press the centers of the cookie cups down using a small spice or sprinkle jar.

Let the cookies cool in muffin tin for 10 minutes before gently twisting the top and transferring the cookie cups to a cooling rack to cool completely. Alternatively, you can place the muffin tin in the freezer to help speed up the cooling process.

Meanwhile, make the white chocolate sauce by heating the cream to a simmer in a small saucepan over medium heat. Immediately remove cream from heat and pour the warm cream over the white chocolate chips in a small bowl. Allow chocolate and cream to sit for several minutes and then whisk vigorously until all of the chocolate is melted. Set aside to cool slightly.

Once the cookie cups have cooled completely, working quickly, use an ice cream scoop to scoop ice cream onto the top of each cookie cup. Immediately top ice cream with the white chocolate sauce, sprinkles and 1-2 M&M's® Easter Sundae. Serve immediately or place in a food storage container or on a serving platter and freezer to serve later.