For the Funfetti Ice Cream

• In a medium mixing bowl, stir together the sweetened condensed milk and vanilla. Set aside.
• In a separate large mixing bowl, whip the cream until soft peaks, either by hand, with a hand mixer, or in the bowl of a stand mixer with the whisk attachment.
• Take 1 C of the whipped cream and gently fold it into the sweetened condensed milk mixture. 
• Then, take the entire sweetened condensed milk mixture and gently fold it into the remaining whipped cream.
• Fold in the rainbow sprinkles.
• Line a half sheet pan with parchment paper and spread the funfetti ice cream mixture in an even layer about ½” thick. Try  to keep the shape as close to a rectangle as possible. It should spread almost to the edges of the pan, but not quite. Freeze for at least 6 hours, up to overnight.

For the Sugar Cookie Bars

• Preheat the oven to 350.
• In the  bowl of a stand mixer, beat the butter and sugars for 3 minutes, scraping down the bottom and sides of the bowl as needed.
• Add the eggs and vanilla and mix for another minute.
• Add ½ of the flour and mix until just combined. Add the remaining flour and mix until the dough starts to pull away from the sides of the mixing bowl. 
• Spray a full sized sheet pan with non stick spray, then roll the sugar cookie dough into an even layer, all the way to the edges of the pan. They dough will be about ¼” thick.
• Bake for 17-18 minutes, or until the edges just begin to brown. Let cool completely, then flip out onto a cutting board.

Assembly

• Slice the cookie down the center the shorter way to create the top and bottom of the sandwiches.
• Place the sheet of funfetti ice cream on one side of the cookie bars and top with the other half.
• Use a sharp knife to trim any excess ice cream around the edges.
• Slice into rectangles or squares. Serve.
• Place extras in the freezer in an airtight container for up to 3 months.