Saute mushrooms/cauliflower in 1 tbsp of butter until liquid is released. Remove from heat and set aside.
Crush garlic, ginger and chilies together, preferably in a mortar. If using red (or chili) pepper, combine with crushed garlic and a little olive oil. Cover and set aside.
In a medium saucepan, bring the stock to a boil. Cover and keep hot.
In a larger saucepan, melt 1 tbsp of butter in 1 tbsp of the olive oil. Add the onion and cook over medium heat until softened, about 4 minutes. Add the rice and cook, stirring for 1 minute. Gradually add the stock, one cup at a time, stirring constantly and making sure all of the stock has been absorbed before adding more, about 25 minutes total.
When the rice is cooked through but still al dente, add the sauted mushrooms. The risotto is done when the grains are just tender and the sauce is creamy. Remove from the heat and stir in lemon juice, zest, remaining butter and Parmesan. Season with salt and pepper and cover.
In a large skillet, heat the remaining 2 tbsp of olive oil. Add the shrimp, season with salt and pepper, and cook over high heat until the shrimp are almost pink throughout, about 2 minutes. Add the chile/pepper and garlic mixture and cook, stirring for 1 minutes. Stir in the parsley.
Stir the risotto. Spoon into bowls or serving plates. Top risotto with shrimp. Serve with lemon wedges and/or extra parsley.