Add remaining olive oil to the pot, followed by shiitake mushrooms, shallots, and garlic. Season with salt and cook until mushrooms release moisture and begin to brown, and shallots and garlic are soft, about 7 minutes.
Push aromatics to the side and add Arborio rice. Stir to coat with oil and toast for about 2 minutes.
Pour in apple cider vinegar and cook, stirring constantly, until absorbed by the rice.
Begin adding warm broth to the rice, one ladleful at a time, stirring constantly and allowing each addition to be absorbed before adding the next. Add a small cube of remaining butter with each ladle of warm broth. Continue until rice is creamy and cooked to al dente, about 18-20 minutes.
Turn off heat and lay giant red shrimp atop the rice. Cover and steam both rice and shrimp for 15 minutes. Remove shrimp and set aside.
Stir in the crab meat and serve the risotto hot. Garnish with crispy Chanterelle mushrooms, giant red shrimp,