Preheat the oven to 200 degrees C. Lightly grease a large baking tray.
Place the tomato halves on the prepared tray with the halved mushrooms. Season well. Bake for 13 minutes.
Meanwhile, for the eggs, bring a medium saucepan of water to simmer and add the vinegar. Crack open the eggs and gently drop them into the water. Cook for 5 to 6 minutes until softly poached and transfer to a warmed plate with a slotted spoon.
Arrange the spinach onto the mushrooms, drizzle the tomatoes and spinach with the oil then cook for a further 2 minutes until the spinach has wilted.
Squash 1 tomato half into each slice of toasted bread. Then sandwich the mushroom and spinach together and place on top of the tomato toast. Top with the softly poached eggs and serve with an extra roast tomato. Season and serve straight away.
If you haven’t got any fresh spinach then you can use frozen. Instead of soda bread or granary bread, serve on toasted baps or crumpets.