Substitute 1 tin of crabmeat for salad shrimp if desired. You may obtain the lemon juice and required zest from the same fresh lemon.
To make the croustades: cut 2-inch rounds from bread slices. Brush both sides of circles lightly with melted butter; press circles into tiny muffin cups. Make at 450F for 5 minutes
Melt butter in medium microwave-safe casserole on High for 1 to1 1/2 minutes. Stir in flour, then slowly whisk in milk. Microwave on Medium for 2 to 3 minutes, whisking each minute, until hot and thick. Add cheese; stir until cheese melts. Stir in remaining ingredients except paprika.
Spoon a small amount of mixture into each croustade. Sprinkle lightly with paprika. (Can be wrapped well and frozen at this point for up to 3 months)
Bake freshly made croustades at 400F for 5 to 8 minutes, or until brown and bubbly. Bake frozen croustades at 400F for 15 minutes. Quantity will vary from 3 to 4 dozen depending upon pan sizes and desired size.