Beat the egg whites on high until foamy, add the cream of tartar and continue to beat until it forms soft peaks, the add the sugar and cornstarch gradually. Beat until stiff peaks form. (when you think it is done, you probably need to beat it a little more).
Gently fold in the crumbled Biscoff cookies.
Line a baking sheet with parchment paper and pipe or spread the meringue out into two disks (or six if you prefer individual pavlovas)
Place the meringues in oven, then reduce heat to 250 degrees and bake for 1 hour. After the hour, shut off oven, leave the door closed, and LEAVE THE MERINGUE IN for 2 hours until fully cooled.
Once the meringue is fully cooled, set aside in dry place (or store in airtight container if you will be assembling a day or two later).
To make filling: Beat ¾ cup of the heavy cream in cold mixing bowl, until it forms peaks. Mix the other ¼ cup in the Biscoff to loosen it up, then add this to the whipped cream and beat for about a minute.
Break off the top crust of meringue, and top with the Biscoff whipped cream. Layer, if you like.
Top with sliced peaches, and crumbled Biscoff cookies. Serve.
Courtesy of Mom Foodie - Biscoff Peach Pavlova Recipe find it at https://momfoodie.com/biscoff-pavlova/