Spray an ovenproof frying pan with low calorie cooking spray and grease thoroughly. Mix the strawberries with the jam and set aside.
Place the egg yolks and sweetener in a large bowl and beat with an electric whisk for 1 - 2 minutes, until well combined. The mixture will still be runny at this stage.
Wash the whisks in hot soapy water and dry thoroughly before proceeding.
Place the egg whites in a mixing bowl and whisk until stiff peaks have formed.
Tip the whisked egg whites into the egg yolk mixture and, using a large metal spoon, fold in until just combined. Take care not to knock the air out of the mixture.
Place the greased frying pan on a medium heat. When hot, tip in the egg mixture and gently spread out to a diameter of approximately 15cm. Preheat the grill on a medium setting.
Cook the omelette in the frying pan for 2 - 3 minutes, or until the edges start to dry. Carefully lift the edge to look underneath, the base should be light golden.
Place the omelette in the frying pan under the preheated grill, and grill for 1 - 2 minutes until the top is light golden brown.
Transfer the omelette to a serving plate.
Place the strawberry mixture on one half of the omelette and fold the other half over the top. Dust with the icing sugar and serve at once.