Add <quantity>1</quantity> room temperature egg white to bowl and whisk until it starts to foam

Add <quantity>70<unit>g</unit></quantity> of sugar, 1 tablespoon at a time. Whisk continuously until it builds a soft peak. It should look fluffy and glossy

Add <quantity>150<unit>ml</unit></quantity> of heavy cream to a separate bowl and whip until it starts to fluff and looks like a loose whipped cream

Add <quantity>100<unit>g</unit></quantity> of greek yogurt

Add the egg whites and whisk to combine

Add <quantity>½<unit>cup</unit></quantity> of blueberries and slightly crush them in the mixture

Pound <quantity>1<unit>tbsp</unit></quantity> of dry lavender in a mortar and pestle

Add to the bowl and whisk to combine

Transfer to silicone molds

Even out the surface and place in freezer for at least 3h to freeze

Preheat the oven to <temperature>180<unit>°C</unit></temperature>

Add <quantity>250<unit>g</unit></quantity> of rolled oats and <quantity>75<unit>g</unit></quantity> of sugar to a bowl

Add <quantity>100<unit>g</unit></quantity> of cold butter and mix with your hands until roughly combined

Transfer it to a tray and bake for 10m until golden brown. Remove from the oven and let it cool until the crumble is crispy

Add <quantity>100<unit>ml</unit></quantity> of water to a saucepan over medium-high heat

Add <quantity>100<unit>g</unit></quantity> of sugar and <quantity>1<unit>tbsp</unit></quantity> of dried lavender

Add <quantity>¼<unit>cup</unit></quantity> of blueberries and bring it to a boil. Stir until the sugar is dissolved

Remove from heat, strain to a container, and let the liquid cool. Discard the blueberries

Remove the semifreddo from the freezer, unmold and cut in half

Place half in a shallow bowl. Add <quantity>½<unit>tbsp</unit></quantity> of fresh blueberries and the oat crumble to taste

Drizzle the blueberry and lavender sauce over the blueberries and garnish with edible flowers to taste. The blueberry lavender semifreddo is ready

Enjoy this refreshing dessert!