Combine, yeast, salt and sugar in a jug. Stir with a fork. Cover. Stand in a warm, sunny place for 5 minutes or until bubbles form on the surface. Add flour into a large bowl make a well in the center; pour in the yeast mixture and 2 tbsp oil. Mix to form soft dough. Turn dough onto a lightly floured surface. Knead for 5 minutes or until elastic.
Place dough into bowl cover with a damp tea towel and leave in a warm place until it doubles in size. Knock back the dough and cut into 4 roll each piece dough into a 35cm x 45cm rectangle. Place one-quarter of spinach over half of each rectangle. Top with feta and season with salt and pepper.
Fold dough over to enclose filling. Press edges together to seal. Preheat a large skillet pan or BBQ hot plate on medium-high heat. Brush one side of each gozleme with 2 teaspoons oil. Cook for 2 to 3 minutes or until base is golden. Brush uncooked side with remaining oil. Turn over and cook for 2 to 3 minutes or until golden and crisp. Remove to a serving plate. Cut gozleme into quarters. Serve with lemon wedges.