Place butter, milk, cream, garlic, salt, and pepper in a jug.
Mix until combined. Give the cream mixture a taste. Add more salt if required.
Preheat oven to 180°C.
Slice potatoes: Peel the potatoes and slice them. You can also use a mandoline.
Layer 1: Spread 1/4 of the potatoes in a baking dish, then pour over 1/4 of the cream mixture. Scatter some thyme and top with some cheese.
Repeat for the 2nd and 3rd layers.
Do not put cheese of the fourth (last layer)
Cover with lid or foil, and bake for 60-70 minutes or until the potatoes are soft. Use a knife to test for doneness.
Once potatoes are soft, remove foil, top with cheese. Bake for a further 10 to 15 minutes until golden and bubbly.
Let it stand for 10-15 minutes before cutting.
