Begin by rinsing 6 cups of fresh raspberries under cool water. If using frozen, ensure they are thawed and drained.

In a medium saucepan, combine prepared raspberries with granulated sugar and let sit for 5 minutes to enhance flavor.

Place the saucepan over medium heat, bring to a gentle simmer, and cook for about 8-10 minutes.

Use a fork or potato masher to mash some raspberries for a smoother texture.

In a small bowl, whisk together ¼ cup cornstarch and ¼ cup cold water until smooth.

Pour the cornstarch slurry into the raspberry mixture while stirring continuously and cook for 2-3 minutes until thickened.

Remove from heat and stir in 1 tablespoon of lemon juice and ½ teaspoon of vanilla extract.

Add a pinch of salt to balance flavors and allow the filling to cool slightly.

Let the filling cool for 10-15 minutes before using in desserts.