Heat oil in a non-stick pan. Add garlic and sauté till golden. Add onion and sauté till golden. Remove from heat and transfer into a bowl.
Dissolve yeast in 2 tablespoons warm water in a bowl. Add a pinch castor sugar, mix and set aside to activate.
Put flour, 1 teaspoon castor sugar and salt in another bowl and mix. Make a well in the center, add activated yeast and mix. Add some water and mix till well combined.Transfer onto the worktop and knead into soft dough. Spread butter over the dough and knead till it is well incorporated.
Dust some flour in a bowl, transfer the dough into it, cover with damp muslin cloth and set aside to prove for 10-15 minutes.
Grease a loaf tin with some butter and dust with some flour.
Transfer the dough onto the worktop and knock back to release excess air. Put the garlic-onion mixture over it and knead well.
Transfer the dough into the greased loaf tin, flatten lightly, cover with damp muslin cloth and set aside to prove for 10-15 minutes.
Preheat oven to 180º C.
Put the loaf tin on the baking tray. Place the baking tray in preheated oven and bake for 20 minutes.
Slice and serve.