Heat oven to 375°F. In a large skillet coated with cooking spray, cook shallots over medium-low heat, stirring, 3 minutes. Add shiitakes; stir until soft, 5 minutes. Add spinach and 1/2 chopped garlic; stir about 3 minutes. Season with salt and pepper. Remove from heat. Whisk milk and flour in a small saucepan over medium-low heat. Bring to a boil, then reduce heat to a simmer, whisking, 5 minutes. Whisk egg yolks, one at a time, into milk-flour mixture; whisk in cheeses and mustard. Season with salt and pepper. Fold spinach mixture into egg mixture. Beat egg whites in a bowl until firm peaks form. Stir 1/4 whites into spinach mixture; fold in remaining whites. Coat a 1 1/2-quart souffle dish with cooking spray. Spoon mixture into dish. Bake until puffed and golden, 30 minutes. In a medium skillet coated with cooking spray, cook remaining chopped garlic, stirring, until lightly golden. Stir in tomatoes; cook 3 to 4 minutes. Stir in basil, thyme and vinegar; season with salt and pepper. Spoon souffle onto plates; top with tomatoes. 1 cup cubed roasted butternut squash per person. Toss squash with 2 teaspoon olive oil; season with salt and pepper. Bake at 400°F until tender, 30 minutes.