Preheat your oven to 350°F (175°C) and line a 9x13-inch baking pan with parchment paper.

In a large mixing bowl, combine 2 cups of all-purpose flour, 1/2 cup of granulated sugar, and a pinch of salt. Cut in 1 cup of softened butter until the mixture resembles fine crumbs.

Press the crumb mixture firmly into the prepared baking pan and bake for 15 to 20 minutes until lightly golden.

In a separate bowl, whisk together 2 large eggs until frothy. Gradually mix in 1 cup of granulated sugar, 1/4 cup of flour, and 1 teaspoon of baking powder until smooth.

Fold in 2 cups of diced rhubarb until well coated.

Pour the rhubarb mixture over the cooled shortbread crust and bake for 40 to 45 minutes or until set and slightly golden.

Allow to cool completely in the pan on a wire rack before lifting out and slicing.

Slice the bars into squares or rectangles and serve at room temperature.