Creamy Gratin Cook Ahead and Freeze
Instead of having it fully cooked then freeze/chill, then reheat, I'm going to just prepare it up till a par-boiled stage before freezing (or chilling if it's prepared just the night before). Potatoes don't freeze well raw but par-boiled ones do, and I have done so many times with homemade chips.
7 large potatoes, rinsed, peeled and thinly sliced
1 large red onion, finely chopped
1 large clove of garlic, minced
1 teaspoon dried thyme
1 bay leaf
200ml cooking cream
400ml fresh milk
Freshly ground salt & pepper
Grated mature cheddar cheese (I've used about 6 tablespoons)
1 tablespoon breadcrumbs
Sprinkle of paprika powder
As I need to have the potatoes at a par-boiled form before freezing, I'm cooking this different from the usual way.
Using a large wok (I find this makes the stirring easier, and it's just the right size), add the cream, garlic, onion, bay leaf and thyme. Cook for about 3-4 minutes till onion is soft then pour in the milk followed by the salt and pepper.
Bring the mixture to just about boiling point, slowly add in the potato slices. Cook it for another 4-5 minutes, stirring slowly constantly.
The cream-milk mixture will thicken slightly through the process, due to evaporation of water content as well as the starch being released from the potato slices. By this time the potato slices will be soft enough but not breaking easily yet, turn the heat off.
Fish out the bay leaf. In a large deep baking dish, arrange the slices in a slightly overlapping manner, scooping the cream-milk mixture and onion & garlic over every layer, till the dish is filled up or the slices are all used.