To make the jam, wash the strawberries and put them in a saucepan with the sugar and juice of half a lemon. Heat over a medium heat for 25 minutes or until it starts to thicken up. Put by and leave to cool. If you want to make enough to keep for other uses, follow the same method with double the quantities, and once it has cooked, pour the mixture into a jam jar, tighten the lid and turn upside down to ensure a tight seal.
To make the dessert, whip the cream using an electric whisk and add the 75 g of sugar. Mix with the yogurt in a bowl and put by. Put a spoonful of the strawberry jam into the bottom of the dessert glass, add the cream-and-yogurt mixture and top off with the chopped pistachios.