📖 Instructions

1. Preheat your oven to 350°F (175°C). Grease a 9-inch springform pan and line the bottom with parchment paper. This ensures the cake releases easily.
2. In a large bowl, cream together 1 cup (2 sticks) of unsalted butter, softened, and 1 3/4 cups of granulated sugar until light and fluffy. An electric mixer makes this much easier, but you can do it by hand if you're feeling ambitious!
3. Beat in 2 large eggs, one at a time, then stir in 1 teaspoon of vanilla extract. Make sure each egg is fully incorporated before adding the next.
4. In a separate bowl, whisk together 2 1/2 cups of all-purpose flour, 1 teaspoon of baking powder, and 1/2 teaspoon of baking soda. This ensures even distribution of the leavening agents.
5. Gradually add the dry ingredients to the wet ingredients, alternating with 1 cup of sour cream, beginning and ending with the dry ingredients. Mix until just combined. Be careful not to overmix; overmixing can result in a tough cake.
6. Gently fold in 2 cups of chopped fresh rhubarb and 1/2 cup of sunflower seeds. Distribute the rhubarb and sunflower seeds evenly throughout the batter.
7. Pour the batter into the prepared springform pan and spread evenly.
8. In a small bowl, combine 1/4 cup of sunflower seeds and 1 tablespoon of granulated sugar. Sprinkle this mixture evenly over the top of the cake.
9. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs attached. Ovens vary, so keep a close eye on it!
10. Let the cake cool in the pan for 10-15 minutes before releasing it from the springform pan. Then, transfer it to a wire rack to cool completely. This prevents the cake from breaking apart.
11. Once the cake is completely cooled, dust with powdered sugar, if desired. Slice and serve. Enjoy the delightful combination of tart rhubarb and nutty sunflower seeds!