Mix together the flour, sugar, salt, and cinnamon for the crumble. Use your fingers or a pastry cutter to cut the butter into the mixture. Press well until the mixture clumps together well.
Store in the freezer until needed.
Slice the strawberries and mix with the cornstarch, sugar, and vanilla.
Arrange in an 8-inch baking pan or deep pie dish.
Top with the streusel. Bake for 40 - 50 minutes, or until the juices from the strawberries is vigorously bubbling. If the crumble topping is darkening too fast, you can place aluminum foil over it after 30 minutes.