To make the jam, chop the strawberries into small cubes.

Cook the strawberries, sugar, water, cornstarch, salt, and vanilla extract on the stove over low heat for 30-45 minutes, stirring intermittently until mixture is thick enough to coat the back of a spoon.

After the strawberries are thick enough, use an immersion blender to blend the strawberry chunks into a jam.

Remove the strawberry jam from the heat and let it cool at room temperature for 1-2 hours, then refrigerate it until it's ready to use.

Preheat the oven to 350F/177C convection (325F/163C conventional) and line a large baking sheet sheet with parchment paper.

To make the turnovers, take 3 Athens Phyllo Dough Sheets and cut them in half longwise. Brush the top sheet with melted butter, add 1 tablespoon of strawberry jam on one side, and fold them into triangles, brushing each side with butter as you fold it. Repeat this process until there are no more sheets, which will yield 10 turnovers.

Transfer the turnovers to the prepared pan and bake for about 15 minutes, until they're golden brown. Let them cool at room temperature for at least 5 minutes.