And then suddenly it's summer - blazingly hot, electric blue-sky summer. The heat blasts at 500˚F, and the days start to get inexplicably shorter, even before the dog days have truly begun. The flowers wilt in the heat and you do too, cooling off in barely there dresses and flipflops. Your favourites - the ones that you have waited for with longing and anticipation - make their glorious entrance and just as quickly begin to maddeningly disappear. Juicy peaches; the season's first cherries and strawberries; asparagus so tender green it makes you weak.
1. Heat oven to 325˚F. Line the bottom of a 9-inch springform pan with parchment paper. Butter the paper and sides of the pan. Wrap two layers of foil under the pan, and place it on a baking sheet.
2. In a medium bowl, mix rhubarb, cornstarch and ½ cup plus 2 tbsp of granulated sugar.
4. Blend the remaining 1 cup sugar with lemon zest with your fingers until the zest is distributed evenly throughout the sugar. Set aside.
5. In a stand mixer, cream 1 c butter for two minutes. Add the lemon zest-sugar mixture and cream together with the butter at medium-high speed until it is light and fluffy, about 4 minutes, scraping down the bowl periodically.
6. Add the vanilla bean paste and mix well. Add the eggs, one at a time, mixing well after each addition. Mix in the sour cream, and then the lemon juice.
7. Turn the mixer to low, and slowly add the flour mixture, ¼ cup at a time, until well combined, scraping down the bowl periodically. The mixture should be very light and fluffy. Set aside.
5. Heat all of the brown sugar and remaining ¼ c butter in a pan over medium heat. Whisk until smooth and bubbling, about 2 minutes.
6. Pour the brown-sugar mixture into the prepared cake pan, then spoon in the rhubarb and its juices. Spoon in the batter so it covers all of the rhubarb, smoothing out the top evenly.