For the vegan spanakopita, first defrost the spinach, squeeze it out and cut it slightly smaller. Dice the tomatoes and finely chop the garlic. Mix silken tofu with spinach, tomato cubes and garlic. Season well with salt and pepper.
Preheat oven to 180 °C top and bottom heat. Brush the quiche dish with olive oil. Place filo pastry sheets all around the dish so that half of them hang over the edge. Keep brushing olive oil between sheets.
Pour in spinach mixture and smooth out. Loosely fold overhanging pastry sheets toward center over filling, brushing again and again with oil. Bake vegan spanakopita for about 40 minutes, until filo pastry is golden brown and crisp.