Make sure the water is warm to the touch. Add the yeast and mix well. Once it becomes creamy leave and allow to sit for 10-15 minutes.
Add the flour and salt in a medium bowl.
Mix with a dough hook until it forms a ball. Beat for a further 15 minutes to increase the elasticity of the dough.
Turn the dough out into a bowl and pour over 80ml of the olive oil.
Place in a clean, lightly greased bowl and cover with a damp tea towel. Set aside in a warm, draught-free place for 40 minutes or until the dough doubles in size.
Knead for 1 minute or until dough is knocked back to its original size.
Pre-heat the oven to 220C. Place the dough onto an oven tray, I prefer a heavy cast iron baking dish. Spread into the dish and again allow to rise.
Peel and slice the onions. Add into a pan with the remaining Olive Oil on a high heat.
Allow to caramelise and soften. Remove from heat to cool.
By this time the Foccacia dough should have doubled in size again.
When cool spread the onions evenly over the dough.
Sprinkle with sea salt.
Bake in preheated oven for 35-45 minutes or until golden brown. Remove from heat and cool.
Serve warm or at room temperature.