Hanna Winery & Vineyards, which produces a minerally, food-friendly sauvignon blanc, will  celebrate its 25th anniversary at 4 p.m. Saturday with a  blending competition and winemaker dinner  at the Alexander Valley tasting room.

Founded in 1985 by Dr.  Elias Hanna, who purchased 12 acres in the Russian River Valley, the winery has since grown to include 600 acres in the Russian River, Alexander Valley and the Mayacamas Mountains of Sonoma.

Saturday’s celebration will uncork with  teams of guests trying  to recreate Hanna’s popular Bordeaux blend: the Bismark Mountain Vineyards Titan. The winning team will receive a three-year vertical collection of the Titan. The judging panel includes Hanna Winery President  Chris Hanna, winemaker Jeff Hinchliff and assistant winemaker  Marti Quan.

Duskie Estes and John Stewart of Zazu in Santa Rosa will prepare the  dinner, which concludes with this  Rhubarb Upside Down Cake with Cardamom Gelato. For more information, go to hannawinery.com.

 Rhubarb Upside Down Cake

Makes 1 cake

For topping:

6 tablespoons unsalted butter

1 cup brown sugar

1/3 cup heavy cream

2 cups diced rhubarb

For the cake:

½ cup unsalted butter, soft

1 1/3 cup sugar, divided

1 ½ cups flour

2 teaspoons baking powder

¼ teaspoon salt

1 teaspoon vanilla extract

1 teaspoon almond extract

¾ cup milk

4 egg whites

Preheat oven to 350 degrees.

In a small saucepan over medium heat, make caramel by melting the butter and sugar and let simmer about 4 minutes. Add the cream. Prepare a springform, round cake pan with nonstick spray. Pour about a quarter of the caramel into the bottom of the pan. Sprinkle the rhubarb on top of the caramel.

In a stand mixer, combine the butter with 1 cup of the sugar. Sift the flour, baking powder and salt. Alternately add the dried ingredients and the milk to the butter mixture. Whip the egg whites with the remaining one-third cup sugar and fold in.

Bake  about 45 minutes until toothpick comes out clean. Let set for about 5 minutes, but be sure to turn over while the caramel is still fluid. (if you forget, just reheat in the oven.) Garnish with a little extra caramel and the cardamom gelato or whipped cream.

 Cardamom Gelato

3 cups whole milk

3 cups heavy cream

2 cups sugar

½ teaspoon ground cardamom or 1 tablespoon cardamom pods

Combine all ingredients in a saucepan and bring to a boil. Let cool. If using pods, strain out. Freeze in ice cream machine according to the directions.