Here's the recipe I demonstrated at the Minnesota State Fair on Opening Day. (Pat' Sinclair's original recipe called for all-white sugar and no cardamom.) Have fun!
Rhubarb Cake with Lemon Butter Sauce
-- Adapted from "Scandinavian Classic Baking" by Pat Sinclair
2 cups all-purpose flour
1/2 cup + 1 tbsp. granulated sugar
1/2 cup brown sugar, packed
2 teaspoons baking powder
1/4 tsp. salt
1 cup milk
3 tbsp. butter, melted
1 cup chopped rhubarb
1 tsp. cinnamon
1/2 teaspoon ground cardamom
1 cup sugar
1/2 cup butter
3/4 cup heavy whipping cream
2 tbsp. lemon juice
Heat oven to 375 degrees F. Lightly grease or spray a 9- by 9-inch pan.
Combine flour, 1/2 cup each sugar and brown sugar, baking powder and salt in a medium bowl. Add milk and butter and whisk until smooth. Stir in the rhubarb. Pour into the prepared pan.
Combine the remaining 1 tbsp. sugar, cinnamon and cardamom in a small dish. Sprinkle over the batter.
Bake 30-40 minutes or until a wooden pick inserted in the center comes out clean. Cool slightly on a wire rack.
For the sauce, combine the sugar, butter and whipping cream in a small saucepan. Bring to a boil over medium high heat, stirring constantly. Reduce the heat to low and simmer 5 minutes or until slightly thickened, stirring occasionally. Stir in the lemon juice. Serve the sauce warm or refrigerate until needed.