In a bowl, sift together flour, cocoa powder, baking soda, baking powder, salt and instant espresso powder. Set aside.In a large mixing bowl or the bowl of a stand mixer, cream butter and brown sugar until light and fluffy, about 2 to 3 minutes. Add eggs and mix on medium-high speed, scraping down the sides of the bowl, until incorporated. Mix in vanilla extract.Reduce mixer to low and slowly add dry ingredients until just incorporated.Crush 10 sandwich cookies into smallish size pieces; fold into dough until evenly incorporated. Cover and chill dough for at least 30 minutes until workable.While dough is chilling, preheat oven to 350 degrees F. Line a baking sheet with parchment paper and set aside.Carefully remove the filling from the remaining 50 cookies. Rather than twisting, prop the cookie up vertically and use a thin knife or offset spatula to ‘slice’ the filling from one side of the cookie. Keep the sliced-off cookie where it is, and then slice off the other side. Carefully separate filling. Stack two rounds of cream together, and repeat with remaining cookies until you have 25 stacks. You can bag and store the plain cookies for another use (they make a great pie crust!)Use a medium cookie scoop to form 1 1/2-inch balls (approximately 35g each). Split ball in half, roll each half into a smooth ball and then flatten it in the palm of your hand. Place one stack of cream filling in the center, then place the other flattened ball on top. Press around the edges to seal, and form into a puck-shape. Place on prepared cookie sheet. If desired, you can press a few pieces of crushed-up cookie on top of each dough puck (it makes for a nicer final appearance). Repeat, leaving 2 inches apart on baking sheet (you should be able to fit 8-9 or so on one sheet).Place sheet in freezer for 5 minutes, then bake for 10 to 12 minutes or until cookies have spread evenly and tops are cracked and no longer shiny. Remove from oven and let cool on cookie sheets for 10 minutes, then transfer to a wire rack to cool completely. Repeat with remaining dough, keeping dough refrigerated when not actively using it.Cookies will keep in an airtight container for up to 5 days.