Preheat the oven to 100 degrees F ( 40 degrees C).

Heat mashed strawberries and 1/2 cup white sugar in a saucepan over medium heat.

Whisk water and cornstarch together in a bowl; stir into mashed strawberries. Cook and stir until thickened, about 5 minutes. Reduce heat to low and simmer while preparing remaining ingredients, stirring occasionally.

Whisk milk and eggs together in a bowl; set aside.

Mash cream cheese, remaining 3/4 cup white sugar, and vanilla extract together in a bowl until smooth.

Spread some cream cheese mixture over 1 triangle-shaped piece of bread; top with another triangle-shaped pieced of bread to cover. Repeat with remaining bread and cream cheese mixture to make 8 triangle-shaped sandwiches.

Heat butter in a large skillet over medium heat.

Dip cream cheese-stuffed sandwiches into egg mixture, 2 or 3 at a time; place in the skillet. Cook until golden brown on both sides, about 3 minutes per side. Transfer French toast to a baking sheet and place in the preheated oven to keep warm while cooking remaining sandwiches.

Top French toast with warm strawberry glaze and sliced fresh strawberries; sprinkle with confectioners' sugar. Serve with a dollop of whipped cream.