Recently I arrived to the studio to find a surprise copy of Elisabeth Prueitt's, Tartine All Day and I knew immediately I'd bake from it. I chose a variation on her Lemon Pound Cake and made this Vanilla Rhubarb beauty. I've made it many times now (it's so delicious!) so I'm getting pretty good at rhubarb patterns (so satisfying!), but by far my favourite is the star. It's best done with a guide (I explain that a little lower down), plus there's a short stop motion to illustrate it as well. I'm sure this upside down cake would be wonderful with other fruit as well, I think I'll make it all summer long. :)
Reprinted from TARTINE ALL DAY Modern Recipes for the Home Cook by Elisabeth Prueitt. Lorena Jones Books an Imprint of Ten Speed Press, 2017.
[Find my optional notes highlighted in pink in square brackets.]
The actual recipe is called Lemon Pound Cake, (p 302) the rhubarb is listed as one of the variations (p 305).
Makes 8 to 10 servings (one 10-inch/25cm cake)
[I prefer one 9-inch springform pan, lightly greased & parchment lined. Bake it on a parchment lined baking tray with sides or a lip. Since you're using a springform pan the juice will otherwise seep out and make a huge mess of your oven. The cake will work in a regular greased cake pan, with and without parchment, I just like the results better from a greased and parchment lined springform.]
Unsalted butter, for the pan
Preheat the oven to 350˚F/180˚C
[I used only the weight measures]
1/4 cup/50g granulated sugar
5 stalks rhubarb, trimmed [I used about 8 stalks of greenhouse rhubarb before the outdoor was available, it's less robust during baking so depending on what you're using I'd suggest 5-8 stalks]
4 large eggs, at room temperature
2/3 cup/130g granulated sugar
1/4 tsp salt
1/2 cup/110g unsalted butter, at soft room temperature
2 Tbsp olive oil [I prefer a more neutral oil in this case and used vegtable]
[1 vanilla bean, scraped]
1 Tbsp coconut flour
1/4 cup/60ml water
Finely grated zest of 1 lemon [I omitted this]
3 Tbsp/45ml fresh lemon juice [I omitted this]
1/4 tsp vanilla extract [I used 1 tsp]
1/4 tsp sea salt
3 cups/360g almond flour [I like a mix of natural & blanched]
1/4 cup/36g brown rice flour
1 tsp baking powder
1. Preheat the oven to 350˚F/180˚C. Lightly butter the bottom and sides of your cake pan. [Cut two 9" circles (1 for your guide, 1 for the bottom) and two 15x3" strips from parchment (for the sides), set aside. Fold one circle into quarters. This 1/4 circle will be your guide. Lightly butter the pan, 1 round and both strips of parchment, place the round and strips into the lightly greased pan.]
2. Evenly spread 1/4 cup (50g) granulated sugar over the bottom of the pan. Cut 5 stalks [I used 8, give or take] and fill the pan in a pattern. (I like to to cut and fit the stalks in a star or chevron pattern but you could also lay them side by side.) Fit the rhubarb tightly into the bottom of the pan.
[Here's my process for fitting the rhubarb into the pan:
Place the 1/4 circle guide on a small cutting board. With a paring knife and starting from the centre of the 1/4, cut 2 pieces of rhubarb (flat side down) to fit beside one another with the point in the centre. Trim them to fit the guide exactly. Repeat this process from the centre to the edges of the 1/4 circle. Then, place these rhubarb strips into a 1/4 of the pan (once the sugar is already there). Repeat 4 times (it's helpful to choose pieces of rhubarb that are a similar width). I found I did have to do some re-trimming here and there and it turns out best if the edges are nice and rounded like the pan. Once all the rhubarb is in the pan, cut 2 diagonal lines (like 2 mountains) in each 1/4 (evenly spaced within that 1/4). I found it's easiest to cut from the outside in, on each 1/4, but it works both ways. Finally make 4 tiny rhubarb triangles to fit the 4 triangle spaces you'll be left with.
*You'll also end up with rhubarb scraps, I stewed these with sugar and vanilla bean and have been eating it by the spoonful ever since.]
2. Combine the eggs, sugar, and salt in a large bowl. Using electric beaters or a whisk, beat on high speed until the mixture lightens in colour and triples in volume, 2 to 3 minutes. Continue to beat at a medium speed for 1 more minute, until the air bubbles appear more uniform in size and the mixture forms satiny ribbons.
3. In another bowl, use a wooden spoon to stir together the butter and olive oil. (The butter must be very soft for this to work properly.) [add the scraped contents of 1 vanilla bean]
4. In a small bowl, combine the coconut flour and water and then add to the butter and oil.
5. Add the lemon zest and juice [omit], vanilla, and salt to the butter mixture.
6. Stir together the almond flour, rice flour, and baking powder in a medium bowl. Gently fold the dry ingredients into the beaten egg mixture. Fold about one-quarter of the butter mixture into the egg mixture and then fold in the remaining three-quarters of the egg mixture. Spread the batter evenly over the rhubarb and bake until a cake tester inserted in the center comes out clean, 45-60 minutes. Let cool in the pan on a rack for 5 minutes and then invert onto a serving plate.
The cake keeps, tightly wrapped, for up to 3 days at room temperature or 2 week in the refrigerator. [I love it served with vanilla scented chantilly cream]