Grease a 10-inch fluted tart pan with a removable bottom (at least 2-inches deep).
Place cookies in a food processor; cover and process until fine crumbs.
Melt 1/2 cup butter in a bowl. Add butter to cookie crumbs; process until combined.
Press cookie mixture into bottom and up sides of prepared tart pan; freeze for at least 15 minutes.
Combine 1/2 cup butter and brown sugar in small saucepan.
Cook over medium heat, whisking constantly, until mixture begins to boil.
Cook and whisk 1 minute longer. Remove from heat.
Whisk in 1/4 cup cream until combined. Cool caramel for 15 minutes; pour over bottom of prepared crust.
Freeze for 30 minutes.
Meanwhile, combine remaining butter, 1/2 cup cream, and chocolate chips in a large microwave safe bowl; microwave on high for approx. 2 minutes, whisking every 30 seconds, until chocolate is melted and mixture is smooth.
Whisk in mascarpone until smooth. Set aside.
Beat 3/4 cup cream in another large bowl until it begins to thicken.
Add 1/4 cup confectioners’ sugar; beat until stiff peaks form.
Gently fold whipped cream into the reserved chocolate mixture. Spoon into crust.
Freeze for 30 minutes. Beat remaining cream in a large bowl until it begins to thicken.
Add remaining confectioners’ sugar and vanilla; beat until stiff peaks form.