Beat butter and sugar in large bowl until fluffy. Add egg, rum and vanilla then beat until well blended.
Sift flour, cocoa, bicarb soda and salt into small bowl. Stir dry ingredients into butter mixture. Mix in caramel bits and almonds.
Drop dough by heaping tablespoonfuls onto a large ungreased baking tray, spacing 5cm apart. Bake until biscuits puff slightly and crack on top but are still soft to touch, about 11 minutes. Let biscuits cool on tray 1 minute. Transfer biscuits to rack and cool completely. Repeat shaping and baking with remaining dough.