In a medium saucepan, combine sliced strawberries, lemon juice, and sugar. Cook over medium-low heat for about 10 minutes until softened.

Mix cornstarch with cold water in a small bowl and then add to the pan. Continue cooking until thick, about 2-3 minutes.

On a sugar-sprinkled surface, unfold and roll out puff pastry to about 1/8-inch thick.

Spread a thin layer of strawberry sauce over the pastry, leaving a border. Make a light indentation down the center.

Roll each side toward the center to form a log and wrap tightly in plastic wrap. Chill for 30 minutes.

Preheat oven to 350°F (180°C). Slice the log into ½-inch thick pieces and place on a baking sheet.

Bake for 25-30 minutes until golden brown and flaky. Allow to cool slightly before transferring to a wire rack.

Serve warm or at room temperature, possibly with vanilla ice cream or whipped cream.