Insert the grill plates turn the machine up to 'High'.
Whilst the plates are heating, cut the garlic clove in half and rub over the ciabatta soldiers and tomato halves. Drizzle them with olive oil and once the machine is pre-heated clamp them down between the two plates and cook for 3-4 minutes until charred. Remove from the plates and set aside.
Switch off the 2 in 1 Grill & Sandwich Maker and allow the plates to cool. Once cool, carefully remove the grill plates and attach the sandwich plates. Heat the machine to High.
Once hot, spritz or brush the plates with a little oil and pour the egg whites into the bottom sandwich plate, filling the four triangles nearly to the top. Tear up the mushrooms, feta and remove the thyme leaves from their stalks and sprinkle it all into the triangles. Close the lid and cook on high for 5 minutes.
Once cooked, carefully remove the frittata from the plates and serve with the garlic toasts.