Step by step recipe:

1. 5 min.
   Put into a food-mixer bowl: 500 g plain white flour (French Type 65), 9 g salt, 15 g yeast, 250 g milk (at fridge temperature, so really cold), 75 g butter and 50 g Soured dough (if possible).
2. 10 min.
   Knead on slow speed for 10 minutes. This makes a fairly firm dough.
   
   Note: For the best way to knead, see: A few tips for effective kneading at home.
3. 5 min.
   Cut the dough into 3 pieces of equal weight.
4. 5 min.
   Put one piece of plain dough back in the bowl and and 50 g Pesto and 100 g green olives (chopped).
   
   Knead until well mixed in.
5. 2 min.
   Gather the green dough into a ball, transfer to a clean bowl and cover with a plastic sheet.
6. 5 min.
   Put another piece of plain dough into the bowl and add 30 g tomato paste. If you would like a stronger tomato flavour, you can add a little powdered tomato soup (about 1/2 a sachet), as shown in the photo.
   
   Knead until well mixed in.
7. 2 min.
   Gather the red dough into a ball, transfer to a clean bowl and cover with a plastic sheet.
8. 5 min.
   Put the last piece of plain dough into the bowl and add the chopped 50 g Caramelized Onions.
   
   Knead until well mixed in.
9. 2 min.
   Gather the white dough into a ball, transfer to a clean bowl and cover with a plastic sheet.
10. 1 hour 30 min.
    Leave the dough to rest for 1 hour 30 minutes.
11. 5 min.
    After resting, cut each piece of dough into 3 (if you are making 3 loaves, that is).
12. 20 min.
    Roll the dough into balls, cover with a plastic sheet and leave to rest for 30 minutes.
13. 1 hour
    After this, roll the dough into long "sausages" the length of your loaf tin or mould.
    
    Place a roll of dough of each colour in each tin, cover with a sheet of plastic and leave to rise for 1 hour.
14. 30 min.
    Preheat the oven to 460°F (240°C).
    
    Bake for about 30 minutes.
15. 
    The best part of this recipe is when you slice open the loaf to reveal the three lovely colours before you eat it...