Making a cottage pie crispy on top isn't hard, it's all about the quality of your potato mash. Frist before mashing your potatoes they will need to be dry, if you have watery potatoes the top will never crisp up. You can do this by draining the potatoes, putting them back into the pot, and letting them sit for 2-3 minutes. The steam from the potatoes and the residual heat from the pot will help to dry them out. Second, use a fork to create texture on the top of the mash after it has been spread over the mince filling. a textured cottage pie top will help towards it becoming crispy on top. Thirdly adding cheese on top will not only add flavor it will crisp up as well. Forth and lastly cook your cottage pie in a preheated hot oven at 180°C or 365°F for 30-40 minutes. Knowing how to make cottage pie crispy on top will take your cottage pie from great to outstanding. Follow these four steps to create a cottage pie that the family will love.