For confit garlic, combine garlic and oil in a saucepan and poach over low heat for 15-20 minutes or until garlic is soft. Remove from heat and cool. Garlic will keep in its oil, refrigerated, in an airtight container for up to 1 month.
Combine yeast, whole-wheat flour and 340ml lukewarm water in a large mixing bowl and stand for 1 hour or until foamy.
Combine plain flour, 3 tsp salt and thyme with yeast mixture and stir to combine, then transfer to a lightly floured work surface and knead for 10 minutes or until smooth and elastic. Place dough in an oiled bowl, turn to coat, then cover with plastic wrap and stand for 1 hour or until doubled in size.
Knock down dough, transfer to a lightly floured work surface, press out into a 20cm x 30cm rectangle, scatter over confit garlic cloves and drizzle with a little confit oil, then fold over one-third of the dough lengthways, then remaining third to enclose. Place on a lightly floured oven tray, cover with a clean tea towel and stand for 2 hours or until doubled in size.
Preheat oven to 250C. Bake for 5 minutes, then reduce heat to 180C and bake for 40 minutes or until golden. Serve warm with butter on the side. Garlic bread will keep, stored in an airtight container, for 3-4 days.