Cheesy Bean & Toasted Sourdough Bake

• 0.25 cup extra virgin olive oil
• 1 brown onion, finely chopped
• 4 anchovy fillets
• 3 cloves garlic, minced
• 1 400g tin of whole peeled tomatoes
• 0.25 cup pizza sauce (or tomato paste)
• 2 400g tin white/cannellini beans
• 2 cup baby spinach leaves
• 2 cup shredded pizza cheese
• 4 slices of sourdough bread, toasted