In a deep pan set over medium heat, add the onion and cook until soft then add the garlic and cook until fragrant.
Add the rice and stir, cooking for a minute. Pour in the wine and cook until absorbed, stirring regularly.
Add the stock, one ladle at a time, cooking and stirring continuously until the rice is cooked to your preference. This will take 20-25 minutes.
While the risotto is cooking, prepare the chicken and mushrooms. Slice the chicken breasts in half horizontally, resulting in two thin fillets.
Season flour with salt and pepper then cover the chicken with the flour. Heat a large pan over medium-high heat and add a splash of oil. Cook the chicken in the pan until golden brown on both sides, approximately 2-3 minutes per side. Remove from the pan and set aside.
Wipe out the pan then add a knob of butter and add the mushrooms and garlic. Cook until golden brown then season with salt, pepper, lemon juice and parsley. Add the chicken back into the pan and allow to stay warm while you finish the risotto.
Once the risotto is cooked, stir in the butter, spinach and Parmesan then season to taste.
Serve the risotto topped with the chicken and mushrooms and a sprinkling of fresh parsley and Parmesan.