- 3/4 cup (1 1/2 sticks) unsalted butter, room temperature, plus more for pan
- 2 1/4 cups all-purpose flour, plus more for pan
- 2 1/4 cups granulated sugar
- 1/2 teaspoon finely grated lemon zest
- 5 large eggs, room temperature
- 2 teaspoons rose water
- 1 teaspoon vanilla extract
- 1/2 teaspoon kosher salt
- 1/2 teaspoon baking powder
- 1/4 teaspoon baking soda
- 3/4 cup plain yogurt
- 3/4 cup plus 2 tablespoons raw pistachios, toasted and chopped
- 8 ounces rhubarb (2-3 stalks), trimmed
- 2 1/2 cups powdered sugar
- 2 tablespoons milk
- 1 tablespoon rose water
- 1/2 teaspoon vanilla extract
- 1/8 teaspoon salt
- 2 tablespoons dried rose petals
- 2 tablespoons raw pistachios, toasted and chopped
- 12-cup Bundt pan
- Preheat oven to 350°F. Butter and flour Bundt pan, tapping out excess flour.
- Rub together granulated sugar and lemon zest with your fingers in a large bowl until fragrant. Using an electric mixer on medium speed, cream lemon sugar and 3/4 cup butter until light and fluffy, about 4 minutes. Add eggs 1 at a time, scraping down sides of bowl and beating well between each addition. Beat in rose water and vanilla extract on medium-low speed until just combined.
- Whisk 2 1/4 cups flour, salt, baking powder, and baking soda in another large bowl. With mixer on low, add dry ingredients to lemon sugar mixture in 3 additions, alternating with yogurt in 2 additions, beginning and ending with dry ingredients, scraping down sides and bottom of bowl as needed. Fold in pistachios.
- Cut rhubarb crosswise into 2 1/2″ pieces. Using a mandoline set to 1/4″ or a very sharp knife, slice rhubarb lengthwise, maintaining as much red skin on stalks as possible.
- Pour one-third of the batter into prepared pan and smooth surface. Add half of the rhubarb, nestling pieces side by side to form a thick ring on top of batter. Pour another third of the batter on top of rhubarb layer; smooth surface. Repeat with remaining rhubarb and batter.
- Bake cake until the surface is cracked and golden brown, springs back to the touch, and a tester inserted into the center comes out clean, 50–60 minutes. Let cake rest in pan 10 minutes, then turn out onto a cooling rack.
- Whisk powdered sugar, milk, rose water, vanilla extract, and salt in a medium bowl until well combined. Glaze should be pourable but stiff enough to hold its shape-it can be thickened with more powdered sugar or thinned with more milk if needed.
- Using a spoon, drizzle rose glaze over cooled cake, holding the spoon a few inches above the cake. While glaze is still wet, sprinkle rose petals and pistachios on top.
- Cake can be baked, cooled, wrapped in plastic, and stored at room temperature up to 3 days. Glaze can be made and stored in an airtight container at room temperature up to 5 days.