Melt the butter in a pot, then let it cool down a little. Finely crumble the biscuits. Fill the biscuits into a large freezer bag, brush out the air and roll the biscuits with a cake roll.
Mix cookie crumbs and butter well.
Spread a thin layer of oil on 8 tartlet cups with a lifting base (each approx. 10 cm Ø). Spread the breadcrumb mixture into the tartlet cups and press firmly into the bottom. 1⁄8 Press the crumb mixture into each pan with a tablespoon as a base and press down firmly at the edges.
Chill the ramekins.
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Bring the milk to the boil, remove from the stove and allow the bag of chai tea to steep for 6 minutes. Mix cream cheese and sugar. Stir in eggs, egg yolk and chai milk.
Spread the mixture evenly in the moulds. Bake in the oven for about 25 minutes.
Take out and let it cool down for about 30 minutes. Carefully remove from the moulds. Leave to cool and sprinkle with some brown sugar before serving.