In a food processor, process the flour, sugar and salt for about 10 seconds.
Then add the chunks of butter and process until the mixture looks like coarse crumbs.
Add the egg yolk and process again until the egg is thoroughly combined.
Press the mixture into a 10 inch tart pan (making the sides slightly higher than the centre) and bake for about 15-18 minutes. Again make sure to prick the tart with a fork several times while baking, and watch it carefully.
Remove from tart pan and cool.
The Cream Filling:
In a sauce pan mix together sugar, corn starch, flour and salt.
On medium-high heat, slowly stir in the cream. Stir constantly and bring to a boil, then reduce heat. Stir until thick.
Stir a little of the hot mixture with the egg, then return to the saucepan, and bring to a boil, stirring constantly.
Remove from heat, cool then chill.
Once chilled, add sour cream and mix well. I used a hand blender to make a creamy consistency.
The Strawberry Topping:
Cut 2 1/2 cups of strawberries into quarters. Set aside.
Take the other 1/2 cup of strawberries and puree. I used a hand blender.
Put the strawberry puree and water into a saucepan and bring to a boil. Reduce heat.
In a separate bowl, combine sugar and corn starch. Then add the mix to the strawberry puree.
Stir constantly until sauce thickens. Set aside to cool.
Once the sauce has cooled, pour it over the cut strawberries, and mix well.