Preheat the oven to 180°C and grease a 23cm, round, springform cake tin.
Blitz the bread in a food processor into bread crumbs.
Add the melted butter and blitz again to coat the bread crumbs.
Press the breadcrumbs into the bottom of the springform tin to form a base and bake for 15 minutes. Set aside.
Sauté the onions in the olive oil, thyme, parsley and a dash of salt and pepper until the onions have softened (approx. 10 minutes). Set aside to cool.
Mix the ricotta, eggs, cream and a pinch of salt and pepper together with an electric beater until smooth.
Add the cooled onions and stir to combine.
Pour the ricotta mixture over the bread crumb base and scatter over the cherry tomatoes.
Bake in the centre of the oven for approximately 50 minutes or until the centre of the tart is just set.
Allow to cool for 30 minutes before loosening around the edge of the tart with a knife and releasing from the springform tin.