Melt the fat in a pot. Pour into a mixing bowl. Add orange juice and sugar and beat until frothy with the whisk of the hand mixer. Add cinnamon and rum. Fold in flour, oat flakes and flaked almonds. Cover and chill for about 1 hour. Use a teaspoon to heap small blobs on three baking sheets lined with baking paper.
Leave enough space on the baking tray between the individual cookies, as they will run apart during baking. Bake the trays one after the other in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 10-12 minutes. Let the oatmeal cookies cool down. In the meantime, chop the chocolate coating and melt it on a hot water bath. Dip 1/3 of the cookies into the couverture and let them dry on a cake rack. Arrange on a cookie plate and serve
waiting time approx. 2 hours