Add 2 tbsp olive oil to a large saucepan. Once shimmering, add the onions and a generous pinch of salt. Cook, stirring occasionally, until the onion is softened and transluscent - about 5 minutes.
Add the garlic and tomato paste and cook until fragrant and the tomato paste begins to darken - 2-3 minutes.
Add the zucchini, peppers and thyme and season generously with salt. Cook, stirring occasionally, until softened and they begin to release their moisture - about 5 minutes
Pour over the wine and stir to combine. Cook until the strong alcoholic smell has dissipated - 2-3 minutes - before adding the tomatoes and bay leaf. Stir to combine and bring to a simmer. Cook, stirring occasionally, until the vegetables are very tender and the mixture is thick - another 15 minutes - adding a splash of water if needed to deglaze.
Off heat, stir in the basil and remove the bay leaf. Taste to adjust for seasoning, adding more salt and pepper if needed. Serve warm, cold or at room temperature.