Heat oil in large saucepan over high heat. Add chicken and cook, turning halfway, for 6 minutes or until golden. Transfer to a plate. Reduce heat to medium-high and add crushed garlic, onion and fennel. Cook for 15 minutes or until starting to caramelise.
Return chicken and any resting juices to fennel mixture with cinnamon, rice, thyme and stock. Bring to a simmer, reduce heat to low and cook for 2 hours or until rice has broken down. Discard cinnamon and any visible thyme stalks.
Transfer chicken to a chopping board and carefully shred meat from bones, discarding bones and skin. Return meat to soup (add extra hot stock or water, ¼ cup [60ml] at a time, if you like, to reach desired consistency) and stir through lemon juice.
Combine extra garlic, reserved fennel fronds, lemon zest and pecans in a bowl.
Divide soup among serving bowls. Scatter with pecan mixture and drizzle with extra oil to serve.
