Heat the waffle iron. In a medium bowl, sift the flour, salt, baking powder, and sugar. Set aside. In a small bowl, whisk together the eggs, milk, vegetable oil, and vanilla. When the waffle iron is ready to use, mix the wet ingredients into the dry ingredients. Stir until just combined. Stir in the strawberries. Do not overbeat. Pour batter into center of the waffle iron (amount will depend on the size of your waffle iron).