Preheat the oven to 85C/185F or to its lowest setting. Line a baking tray with greaseproof paper.
For the oven-dried tomato confit, place all of the confit ingredients except for the icing sugar into a bowl and mix well to combine. Then, place the tomato halves on the prepared baking tray, cut-side up. Dust with the icing sugar then place into the oven for 25-35 minutes, or until the tomatoes are wrinkled and dried.
Meanwhile, for the tomato vinaigrette, place the sun-dried tomatoes and cherry tomatoes into a food processor and blend until smooth. Strain the mixture through a fine sieve set over a bowl, pushing the mixture through with the back of a spoon until all of the juice is extracted. Discard the pips and skin.
In another bowl, whisk the mustard and vinegar together and season with salt, freshly ground black pepper and the sugar. Whisk in the olive oil until well combined, then mix in the strained tomato juices.
To serve, arrange the sliced mozzarella, cherry tomatoes and oven-dried tomatoes on a serving platter and drizzle over the tomato vinaigrette. Garnish with basil leaves and baby cress.