Last night, I made a cottage pie and cooked it in the oven for 30 minutes, once cooled down I placed it in the fridge.
What would be the best way to reheat this? I've read somewhere that 180 for 45 minutes would do it, but I wondered if this would overcook the mash, which is already crusty from the cook last night?
Further to this, if I was just going to prepare (Cook mince and mash), could I do that and then cook in the oven the following day?
180C (350F) for 45 minutes should do the trick. Just make sure it is piping hot in the middle before serving.
Cover the dish with foil to prevent the crust getting any crustier. You will still want to take it off for the last ten minutes of cooking to crisp it though, as the foil will make it soggy.
You can absolutely prepare Cottage Pie to the pre-baking stage and fridge (or freezer) it until the next day. You need to cool it relatively quickly though - hot food shouldn't sit around for more than a couple of hours. Place the dish in cool water (obviously not over the lip of the dish) and change the water a couple of times as the pie warms it, then cover and put in the fridge or freezer.
If you have the time I recommend you put it in the oven to reheat somewhere between 30 and 60 minutes at 350F depending on how deep it is. If you are in a rush and your dish fits in your microwave (and is microwave safe) you could cut a great deal of time off that by first nuking it until it's mostly heated up and then finishing it off under your oven's grill or broiler to re-crisp the mashed potato. Alternatively you could portion it up and nuke each portion until hot, then crisp the mash using a cooking torch.
