Creating Tangy Raspberry Lemon Bars is a breeze when you follow these steps:

1. Preheat the oven: Preheat your oven to 350°F (175°C) and grease an 8×8-inch baking pan.

2. Make the crust: In a mixing bowl, combine flour, sugar, butter, and salt. Mix until crumbly. Press this mixture evenly into the bottom of the prepared baking pan.

3. Bake the crust: Bake the crust in the preheated oven for about 15-20 minutes, or until lightly golden. Remove from the oven and set aside to cool.

4. Prepare the lemon filling: In another bowl, whisk together the eggs and sugar until well combined. Then add lemon juice, lemon zest, flour, and salt, mixing until smooth.

5. Combine with the crust: Pour the lemon filling over the cooled crust, spreading it evenly.

6. Make the raspberry swirl: In a small saucepan over medium heat, combine the raspberries, sugar, cornstarch, and water. Cook, stirring gently, until the raspberries break down and the mixture thickens. Remove from heat.

7. Add raspberry swirl: Using a spoon, drizzle the raspberry mixture over the lemon filling. Use a knife or toothpick to gently swirl the raspberry through the lemon layer.

8. Bake again: Return the pans to the oven and bake for an additional 25-30 minutes, or until the filling is set and lightly browned.

9. Cool completely: Once baked, allow the bars to cool in the pan at room temperature for at least 1 hour. For best flavor, refrigerate for another hour or more before cutting.

10. Cut and serve: Using a sharp knife, cut the bars into squares. Dust with powdered sugar if desired before serving.