Preheat oven to 180oC, 350oF or Gas Mark 4.
Combine the ground almonds, finely chopped walnuts, grated cheese and breadcrumbs in a mixing bowl with the oil (or melted butter).
Tip this mixture into a deep flan dish and press into place with either your knuckles or a small tea plate to line the dish.
Cut the tomatoes in half and cube the feta cheese. Lay on top of your base.
In a jug, whisk the milk, eggs and seasoning together. Pour gently over the flan.
Pop your gluten free quiche into the oven and bake for around 45 minutes, until the filling has browned and set.
Serve either hot or chilled, perhaps with a fresh salad.