Light Strawberry Mousse with Crème Diplomate and Lemon Crumble

A light strawberry mousse with a hidden centre of crème diplomate and lemon crumble. Fresh, airy and never too sweet – a balanced dessert.

Strawberry Mousse 6

A light dessert: fresh, airy and not too sweet 

I’ve never been much of a dessert person. I find that anything too sweet or heavy tends to do more harm than good, especially after a meal. Such desserts sit heavily in the stomach, disrupting digestion and making an otherwise lovely meal unnecessarily filling. A dessert should complement a meal, not take over. That’s why I prefer desserts that are light, fresh and crisp in flavour.

I tend to reach for fruit and light textures. They're fresh but not heavy, and everyone loves them, even those who usually skip dessert. This dessert is exactly like that: a light strawberry mousse with a citrussy crunch and a soft, creamy centre that you only discover once your spoon is already on its way in.

The idea behind this light dessert

The idea is simple: strawberry mousse, crème diplomate and lemon crumble. It is the way they come together that makes all the difference.

The crème diplomate is made in advance and frozen in half-spherical shapes. I press these into the centre of the mousse later. This way, they are nicely integrated and the dessert remains clearly defined. There are no layers or swirls, just a surprising element that emerges naturally.

Strawberry Mousse 5

On Acidity, Gelatine and a Failed Pineapple Mousse

When I was younger, I once tried to make a pineapple mousse. Everything seemed to be going right, but the mousse simply wouldn’t set. No matter what I tried, it remained a runny cream. After much hesitation, I ended up throwing the whole batch in the bin.

Back then, I didn’t know what I know now.

Acidic fruit can affect how gelatine works. Gelatine normally provides structure by forming a network as it cools. However, in a highly acidic environment this doesn't work as well. Some fresh fruits, such as pineapple, kiwi and papaya, also contain enzymes that break down the network partially. The result is a mousse that remains runny when you want it to be firm.

In this mousse, I add a teaspoon of lemon juice for freshness. Adding a little more would enhance the flavour, but it would also reduce the effectiveness of the gelatine. You could compensate for this with extra gelatine, but in my experience, you still won't achieve the desired light, airy texture.

Recipe – Strawberry mousse with crème diplomate and lemon crumble 

Ingredients for 8 people

Crème diplomate:
  • 180 ml whole milk
  • ½ vanilla pod or 1 tsp vanilla extract
  • 40 g sugar
  • 2 egg yolks
  • 15 g cornflour
  • 15 g butter
  • 100 ml cream
  • 1½ sheets of gelatine
Lemon Crumble:
  • 60 g flour
  • 40 g cold butter
  • 40 g sugar
  • Zest of 1 organic lemon
  • Pinch of salt
Strawberry Mousse:
  • 500 g strawberries
  • 70 g sugar
  • 200 ml cream
  • 2 egg whites
  • 3 sheets of gelatine
  • 1 tsp lemon juice
  • 1 tsp vanilla extract
Finishing:
  • Strawberries, in pieces or brunoise
  • A few leaves of mint or melissa

  1. Preparing the crème diplomate:

    1.  Bring the milk and vanilla to the boil.
    2. Meanwhile, mix the egg yolks, sugar and cornflour together until smooth.
    3. Pour in the hot milk, mixing well, then return everything to the pan.
    4. Leave to thicken over a low heat until you have a smooth, thick pastry cream.
    5. Remove from the heat and stir in the butter.
    6. Leave to cool completely, placing cling film directly on top of the cream.
    7. Soak the gelatine in cold water.
    8. Heat two to three tablespoons of the cooled cream, dissolve the squeezed-out gelatine in it, then mix it back into the rest of the cream.
    9. Whip the cream until it is semi-stiff, then gently fold it into the pastry cream.
    10. Divide the crème diplomate mixture between silicone half-sphere moulds and place in the freezer until firm enough to handle.

    Practical tip:

    Use half-spheres measuring between 3 and 3.5 cm in diameter. This size is large enough to create an element of surprise, yet small enough to ensure the delicate flavour of the straberry mousse is not overshadowed.

  2. How to make lemon crumble:

    1. Rub all the ingredients together with your fingers until they form coarse crumbs.
    2. Spread the mixture evenly on a baking tray and bake at 170°C for 12–15 minutes, or until golden brown.
    3. Leave to cool completely, then store in an airtight container until needed.
    IG 0005 Crumble prep

  3. Preparing the strawberry mousse:

    1. Blend the strawberries, sugar, lemon juice and vanilla together until smooth.
    2. Strain the purée to remove the seeds.
    3. Heat approximately one third of the purée.
    4. Soak the gelatine in cold water, then squeeze out any excess moisture and dissolve it in the warm purée.
    5. Mix this back into the remaining purée and leave to cool.
    6. Whip the cream until it is semi-stiff, then fold it into the purée.
    7. Finally, whip the egg whites until stiff and gently fold them into the mousse.

  4. Assembly and finishing:

    1. Divide the strawberry mousse between eight glasses, leaving enough space at the top.
    2. Gently press a round of frozen crème diplomate into each glass.
    3. Leave the mousse to set further in the fridge.
    4. Just before serving, finish with:
    5. Lemon crumble
    6. Fresh strawberries
    7. A small leaf of mint or melissa.
    Easter 2026 127

If you enjoy desserts that stay light and balanced, you might also like my tiramisu with banana and coffee crumble — creamy and just restrained enough to finish a meal well. 

Tiramisu with banana and coffee crumble.

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