2. On a lined baking tray lay the mushrooms out, sprinkle over the grated garlic, a sprinkle of salt & pepper, and a splash of balsamic vinegar, making sure each mushroom gets some of all the above ingredients.
3. Pop them into the oven, and cook for 12 minutes, then remove and keep hot.
4. In a saucepan, add some olive oil, and then the onions and cook those out for around 10-15 mins until soft and pink.
5. Add the grated garlic, the sugar and the vinegar, and mix through. Let the sugar dissolve, then add the chopped tomatoes and allow this to simmer for 15 – 20 minutes.
6. When cooked, blitz the mixture with a hand blender.
7. To serve, toast the bagels, then give them a drizzle of olive oil. Layer on some of the spinach, then pop two of the mushrooms on each bagel, followed by a spoonful of the tomato relish.
