Cream Filling

Ingredients

• 0.875 cup sugar
• 0.333 cup flour
• 0.125 tsp salt
• 2 eggs
• 2 cups milk, scalded
• 1 tsp vanilla extract

Method

This is a custard — eggs and milk thickened by coagulation of protein, stabilised by starch. The flour acts as insurance against curdling; the sugar dissolves into the milk to raise its temperature and feed browning flavour during cooking. Whisk the sugar, flour, and salt together dry. Add the eggs and beat them in thoroughly — the goal is a smooth paste with no dry streaks, because any flour pocket will lump when it hits the hot milk. The emulsification of egg yolk (which contains lecithin, a natural emulsifier) into the flour-sugar base creates a stable suspension that won't break during the long heat.

Pour the scalded milk slowly — a thin stream, not a dump — whilst whisking hard. Go gradually for the first quarter of the milk; once the mixture loosens, you can pour a bit faster. This controls temperature rise and prevents the eggs scrambling. You're looking for a smooth, thin batter with no lumps.

Set the bowl over a double-boiler of simmering water. The water should not touch the bottom of the bowl, and it should stay at a gentle boil, not a rolling one. Stir constantly for the first 5–7 minutes — the filling will feel thin and pourable. You'll feel the resistance increase against your spoon as the egg proteins denature and the starch granules swell. At around 10–12 minutes, when the mixture coats the back of a spoon and a line drawn through it stays clear, it's at 70°C internally and thick enough. Some recipes push to 15 minutes; the filling will be thicker but risks becoming grainy if you overshoot 82°C. Stop when the surface dimples slightly under the spoon but hasn't broken into visible curdling.

Pull the bowl from the heat. Stir in the vanilla extract. The filling will thicken a little more as it cools — this is the starch continuing to hydrate. Pour it into a clean bowl or onto baking parchment and leave to cool to room temperature, stirring occasionally to prevent a skin forming. If you need it cold, press cling film directly onto the surface and refrigerate.