2Cut a slice from teh top of each tomato. Scoop out pulp,leaving a shell at least 1/4 inch thick. Place tomatoes upside down on paper toweling to drain.
3Sprinkle the inside of each tomato with salt.
In a sauce pan,combine flour and salt.
Blend in milk.
Stir in egg yolk and melted butter.
Add well-drained spinach; blend well.
Cook over medium heat until spinach begins to simmer.
4Spoon mixture into tomatoes,mounding to form a rounded top.
Arrange in a shallow baking dish.
5Bake for 10-15 minutes until tomatoes are cooked but not mushy.