Chocolate Mint-Filled Cookies

I cannot for the life of me remember where this recipe came from. I only know it is simple, a fantastic combination of chocolate and mint, and an easy way to make sandwich cookies. It has occurred to me that if I needed chocolate cookies for making a crumb pie crust and couldn't find those Nabisco cookies that these would be a good substitute.

Rose made these yesterday to add to our Christmas array.

Step 1:
2/3 cup softened butter
1/2 cup sugar

Cream butter and sugar.

Step 2:
1/4 cup light corn syrup
1 egg
6 ounces melted semisweet chocolate

Add corn syrup and egg and blend. Add chocolate.

Step 3:
2 cups flour
2 teaspoons baking soda
1/4 teaspoon salt

Combine flour, soda and salt and add, beating well. Cover and refrigerate 2 hours or put in the freezer for 40 minutes.

Step 4:
1/3 cup sugar

Form dough into 1/2-inch balls (about 96) and roll in sugar. Place 2 inches apart on ungreased cookie sheets. Bake an even number at a time, 12-15 minutes at 350.

Step 5:
48 chocolate covered 1-1/4-inch wide thin mint patties (we use York peppermint patties, sometimes whole, sometimes halved, depending on how accurate we are with the cookie size)

Remove half the cookies from the sheet. Put a mint patty on top, top with another, and press together firmly with spatula so the melting patty spreads. Cool on the rack. They become crisp and hard.