Preheat oven to 425 degrees F. Line a baking sheet with parchment paper. In a bowl combine milk, oil, spinach, basil, tomatoes, and olives. In a large bowl combine flour, baking powder, and 1/2 teaspoon salt. Make a well in center of flour mixture. Add milk mixture all at once; with a fork stir until moistened.
Gently knead dough on a lightly floured surface until dough holds together. Pat into an 8x8-inch square. Cut into nine squares.
Place biscuits 1 inch apart on prepared baking sheet. Brush lightly with milk. Sprinkle with feta cheese and pine nuts. Bake 15 minutes or until golden. Cool slightly before serving.
To give as gift, store cooled biscuits in an airtight container in the refrigerator up to 3 days. Reheat biscuits, wrapped in foil, in 350 degrees F oven 12 minutes. Makes 9 biscuits.