My Aunt's Lace chocolate Sandwich Cookies Recipe

LACE CHOCOLATE SANDWICH COOKIES
My Aunt Sultana bakes often and these were one of my favorite cookies she made for me growing up. She recently shared this recipe with me and I am so excited! They are delicious and I’m happy to make and share them with you.
About 3 dozen sandwich cookies
1 cup unsalted butter
2 ¼ cups light brown sugar
1 tbsp granulated sugar
2 ¼ cups old fashioned oats
1 tbsp all-purpose flour
1 large egg
1 tsp vanilla extract
1 12-ounce bag semi-sweet morsels
Preheat the oven to 350 degrees F.
Add the butter to a heatproof bowl and melt it in the microwave.
Immediately stir in the sugars until completely dissolved.
Stir in the flour and oats until combined.
Then, stir in the egg and vanilla.
Line a baking sheet with aluminum foil and drop batter onto the cookie sheet by the teaspoonful. Leave 1-inch between the cookies.
Bake the cookies for 7-9 minutes, or until the middle part is flat and the edges are golden brown.
Remove the cookies from the oven and allow them to cool.
While the cookies are cooling, melt the chocolate in a heatproof bowl in a microwave.
Working quickly, remove two cookies from the baking sheet and spread a thin layer on underside, and then sandwich the other cookie on top. Repeat with remaining cookies.