Why It Works
- Quickly infusing the milk with zest keeps the lemon flavor bright.
- Cornstarch thickens the pastry cream without imparting a floury flavor.
- Bringing pastry cream to a bubble deactivates the yolk’s starch-dissolving amylase.
- Finishing with butter adds shine and flavor.
- Whisking lemon juice into chilled pastry cream ensures a properly thick texture and fresh flavor.
This silky smooth lemon pastry cream takes advantage of both the fruit’s flavorful zest and bright juice to produce a custard that’s rich and thick and tastes like sunshine. Because the acid in the juice reduces the thickening power of the cornstarch, this recipe calls for both more cornstarch and an extra egg yolk compared to our classic vanilla pastry cream recipe.
This recipe takes advantage of two flavoring techniques: the zest is infused into hot milk to quickly extract its aromatic lemon oils, which are largely responsible for a lemony flavor. The juice, on the other hand, is whisked in at the end, after the paste cream has cooled down, helping to preserve its fresh flavor. The resulting pastry cream is versatile enough to pipe into a cream puff, fill a tart shell, or spread between the layers of a cake.
You can read more about the ins and outs of pastry cream technique in our article and recipe for classic vanilla pastry cream.