Place bread slices on baking sheet. Spray tops of bread with no stick cooking spray. Bake in a preheated 400 F oven until slightly brown on top (about 10-12 minutes). Remove from oven. In large non-reactive saucepan, melt 3 tablespoons butter over medium heat. Add shallots; saute 1 minute. Stir in flour, craeting a roux. Stir roux until just fragrant, but not darkened (about 1 minute). Whisk in milk, salt and pepper. Continue whisking until sauce thickens (about 4-6 minutes). Add shrimp and sherry and continue cooking until shrimp are opaque (about 4-6 minutes). Remove from heat; very gently stir in crab and parsley. Set aside; keep warm. In large skillet, melt remaining 1 tablespoon butter over medium heat. Add garlic; saute 1 minute. Add spinach; saute 3 minutes, breaking up pieces. Stir in salt and pepper. Set aside; keep warm.