Preheat the oven to 350ºF; spray two 8-inch square baking pans with nonstick cooking spray. In a large mixing bowl, stir all of the cake ingredients together until smooth; batter will be thick. Divide the batter in half and pour into two separate mixing bowls, and dye each individually. Pour the batters into the prepared pans, and bake for 28-30 minutes, or until toothpick inserted in the center comes out with few crumbs attached. Allow to cool completely, then cut into cubes.

In the well-chilled bowl of a stand mixer fitted with a whisk attachment, beat the heavy cream until stiff peaks form. Transfer whipped cream to another bowl and place in refrigerator to keep chilled.

Return bowl to mixer. Beat cream cheese until smooth. Add powdered sugar and vanilla; continue beating until smooth and combined.

Add a quarter of the whipped cream and beat until combined. Remove bowl from mixer and use a spatula to fold in the remaining whipped cream. Transfer mousse to a pastry bag or a gallon-sized ziploc bag with the tip of the corner cut off.

Place a layer of the blue cake cubes in the bottom of each jar. Pipe half of the filling into each jar. Coarsely chop all but 7 of the Oreos, then evenly distribute the chopped Oreos among the 7 jars. Add the red layer of cake cubes, followed by the rest of the filling. Garnish each jar with one more Oreo and sprinkles.