1. Preheat the oven to 350°F.
2. In a medium bowl, combine mushrooms, garlic and olive oil. Season with salt and pepper and stir to combine.
3. Arrange mushrooms in a single layer on a rimmed baking sheet. Bake for 15 minutes, or until tender. Set aside.
4. In a medium saucepan, combine chicken stock and saffron. Bring to a boil and remove from heat. Cover and steep for 20 minutes.
5. In a small bowl, combine flour, 1 teaspoon salt and 1/2 teaspoon pepper. Stir to combine. Spread flour mixture on a shallow plate. Spread tempura flour on a shallow plate.
6. In a large heavy bottomed pot, heat oil to 350°F.
7. While oil is heating: Dip crabs in seasoned flour, being careful to cover completely. Then dip crabs in buttermilk, then in tempura flour, being careful to cover completely.
8. Gently place crabs in oil and fry until golden brown. Remove from oil with slotted spoon and drain on paper towel lined plate. Season with salt and pepper.
9. In a large straight-sided skillet, combine risotto and 1/2 cup saffron stock. Cook over medium heat, stirring often, adding 1/2 cup stock at a time until mixture is creamy. Stir in roasted mushrooms, thyme and 1/4 cup Parmesan cheese.
10. Heat broiler in oven.