2. Slice the tops off the tomatoes, reserve these as “lids.”.
3. Scoop out the flesh and juice of the tomatoes into a bowl and mash until pulpy. Set aside.
4. Sprinkle the inside of the tomatoes with the salt and turn upside down on a paper towel to drain excess juice. Set aside.
5. Heat the oil in a large frypan over medium-high heat and sauté the mushrooms, zucchini and herbes de Provence until “al dente” (you're going to cook this mixture again in the oven so you don't want to overcook at this point).
6. Add the reserved tomato flesh and the pearl barley/ wheat berries and stir to thoroughly combine.
7. Add the egg and Parmesan, stir well and remove from the heat.
8. Season to taste.
9. Rinse the salt out of the tomato halves and pat dry with a paper towel.
10. Fill the tomato halves with the mushroom mixture – packing tightly by pressing on the mixture with the back of a soup spoon.
11. Place the tomato halves on a baking tray lined with parchment paper.
12. Place the tomato tops on each tomato, sprinkle with a little olive oil and bake for approximately 30-40 minutes until the filling is hot and the tomato flesh is slightly softened.
13. Optional: you can remove the tops from the tomatoes and sprinkle with some fresh herbs, replacing the tops to serve.