Cookie Dough Brownie Layered Dessert

This recipe was modified from the original at The Farm Girl Recipes.
I found her cookie dough to be too mild for this dessert, so I switched it around a bit to make it stand up to the competition of chocolate on either side of it.

Bottom Brownie Layer:
4 eggs
1 cup canola oil
2 cups sugar
2 teaspoons vanilla extract
1-1/2 cups all-purpose flour
1/2 cup baking cocoa
1/2 teaspoon salt
1/2 cup walnuts, optional

Middle Cookie Dough Layer:
2 sticks(1/2 pound) unsalted butter, room temperature
1/2 16-ounce box packed light-brown sugar
1/2 cup granulated sugar
2 Tab. milk
1 teaspoons pure vanilla extract
1 3/4 cups all-purpose flour
3/4 teaspoons salt
1 ½ cups chocolate chips

Top Glaze Layer:
2 cups milk chocolate chips
2 tablespoons shortening
3/4 cups walnuts, optional

In a large bowl, beat the eggs, oil & sugar. Stir in vanilla. Combine flour, cocoa & salt; gradually add to egg mixture. Stir in walnuts if desired.
Pour into a greased 9 x 13 baking pan. Bake at 350 for 30 minutes or until brownies toothpick test done. Cool completely.
For filling, in a large bowl, cream butter and sugars until light & fluffy. Beat in milk and vanilla. Gradually beat in flour. Stir in mini chocolate chips. Spread over brownies (works best to just press out with clean hands.); chill until firm.

Two layers of the triple layered dessert.

For glaze, in a microwave safe bowl, melt chocolate chips and shortening in 30 second intervals, stirring after each time, until smooth. Spread over filling. Immediately sprinkle with nuts, if desired, pressing down slightly. Yields 3 dozen.