📖 Instructions

1. Preheat your oven to 375°F (190°C). This step is crucial for even baking, so don't skip it!
2. Grease and flour an 8x8 inch baking pan. This will prevent the bars from sticking and make them easy to remove after baking.
3. In a large bowl, whisk together 1 1/2 cups all-purpose flour, 1 cup amaranth flour, 1 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/4 teaspoon salt. Make sure there are no lumps!
4. In a separate bowl, cream together 1 cup (2 sticks) unsalted butter, softened, and 1 cup granulated sugar until light and fluffy. Use an electric mixer for best results.
5. Beat in 2 large eggs, one at a time, then stir in 1 teaspoon vanilla extract. Ensure everything is well combined.
6. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix; this can make the bars tough.
7. In a medium saucepan, combine 4 cups chopped rhubarb, 1/2 cup granulated sugar, and 2 tablespoons water. Cook over medium heat, stirring occasionally, until the rhubarb is tender, about 8-10 minutes. Let it cool slightly.
8. Press half of the dough mixture into the prepared baking pan to form the base. An offset spatula or your fingers can help smooth it out.
9. Spread the cooked rhubarb evenly over the dough base. Try not to leave any bare spots.
10. Crumble the remaining dough mixture over the rhubarb filling. It doesn't have to be perfect – a rustic look is part of the charm!
11. Bake for 30-35 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean. Keep an eye on it to prevent burning.
12. Let the bars cool completely in the pan before cutting into squares. Patience is key here; warm bars will be too crumbly.
13. Dust with powdered sugar, if desired, before serving. This adds a touch of elegance.