For the mint pesto: Mix the sugar and mint in a mortar, grinding well with the pestle. Add the water and mix. Chill if not using immediately.
For the strawberries balsamic sauce: Put the strawberries into a bowl and sprinkle the balsamic vinegar and sugar over them. Add a pinch each of salt and pepper. Toss gently and marinate for 2 to 3 minutes.
For the chocolate espresso ganache: Put the chocolate into a medium heatproof bowl. Bring the cream and the espresso powder to a boil in a small saucepan over medium heat. Immediately pour the boiling cream over the chopped chocolate and let it sit for 1 minute. Using a spatula, slowly stir in a circular motion until all the chocolate is melted, do not stir in too much air. Add in the chopped toasted hazelnuts and allow the mixture to cool. The ganache may be covered and stored in the refrigerator for up to 2 weeks.
To serve: Blend each mix-in into 1 pint softened vanilla gelato. Put back into the freezer to harden.