Place one tablespoon of olive oil in a heated frypan and cook the cubed ocean trout for several minutes until golden on the outside, but pink and glossy inside. Remove and set aside.
Place the pan back onto the heat and add the remainder of the olive oil. Add in the garlic and cook for 20 seconds, Add in the diced onions and cook for several minutes until soft. Combine in the white wine and tomatoes, turn up the heat and cook until the liquid has reduced by half.
Place the cooked spaghettini into a saucepan of boiling water and heat for 1 minute, Strain well and add to the sauce, along with the ocean trout and fresh torn herbs.
Season well and present with grilled sourdough.