Heat up 2 tbsp olive oil in a large saucepan over medium heat. Add the finely diced onions and a little bit salt and saute them until translucent, about 3-4 minutes. Increase the temperature to medium-high heat. Add the Arborio rice and cook for 3 minutes, letting the rice slightly stick to the bottom of the pan and scraping it off.
In a small pot bring the chicken stock to a simmer. Add the saffron to the stock.
Add the white wine to the risotto rice and scrape the rice off the bottom of the pot to deglaze it. Cook over a medium-high heat, stirring continuously until the rice has absorbed the wine.
Add only as much saffron chicken stock to the pan until it covers the rice. Stir often until the rice has absorbed the stock. Repeat this step until you used all the chicken stock and the rice is tender.
Toss in the butter and grated parmesan cheese. Turn off the heat, cover the risotto and make the shrimp.
Cook the shrimps: Heat a medium pan over medium-high heat. Add the butter and olive oil. Stir in the garlic and red pepper flakes. Saute the garlic for just one minute, then add the shrimp. Add the white wine and stir to coat the shrimp. Increase the heat and let cook for 2-3 minutes.
Turn the shrimp and cook for one more minute. Remove the pan from the heat, add the parsley and lemon juice. Season with a bit salt and freshly ground black pepper.
Serve the risotto with shrimp on top and drizzled with the sauce from the shrimp pan.