Rhubarb, Cinnamon, and Cardamom Custard Tart

Hello everyone! I know it's been a quiet couple of months... I've been focusing a lot on my schoolwork, and haven't been able to post any of my bakes since Pi Day. Yes, I have been baking (albeit less frequently), but it is amazing how much time it takes to edit photos, write an article, and compile the recipe! Also, I bake for stress relief and for a break from writing.

I have a little bit of a backlog of recipes, although I am going to post a "fresh" recipe today. I baked this rhubarb, cinnamon, and cardamom custard tart earlier today, and want to write about it while it is still fresh in my memory. I have been wanting to do this bake for quite a while, but couldn't do so until rhubarb was in season. I finally found it at the supermarket a few days ago, so here the tart is!

This tart is my attempt at the signature bake from Series 5, Episode 5 of Great British Bake Off. The challenge is to make a signature family-sized custard tart. Due to the fact that I had to bake for a few different groups of people for tomorrow, I made two such tarts.

I have actually never before had rhubarb- nor cooked with it; this was quite a treat to make. It turned out a little messy, but I now know how to make it a little better next time. Also, the colors of the tart so happen to match the tulips I currently have in my kitchen!

The pastry dough is fairly simple to make. Instead of making my standard pie crust, I made a slightly more enriched dough- I added more sugar than I normally do, and bound the dough together with milk instead of water. Due to the fact that rhubarb is rather tart and I didn't add much sugar to the custard filling, I thought the sweeter dough would help balance out the flavor.

One of the most important steps to this bake is blind baking the pastry crust. Once combining the ingredients and rolling out the pastry, it should be placed in a pan and filled with baking beans (I have two sets of ceramic baking beans, but actual dried beans can work just as well). The crust should be blind-baked with the beans for twenty  minutes, and then for a further twenty minutes with the beans removed. This will ensure that the crust is fully baked and that there are no soggy bottoms! Since the dough is enriched with extra sugar, it is more likely to brown at the edges; this can be mitigated by covering the edges with aluminium foil.

Pastry dough has a tendency to shrink a bit during baking. To minimize the impact this has on the final product, I let extra dough overhang the edges of the tart pan during the first step of blind baking. I will then cut off the excess (either by using a knife or by just pressing the dough down against the edges of the tart tin) for an even finish.

Rhubarb is ridiculously bitter when raw. For this tart, I made a sort of rhubarb compote. I cooked the rhubarb on the stove with sugar and just a little bit of water. Once it was mushy and bubbly, I pureéd it in a blender to make it smooth. This composition formed the base of the interior of the tart, as well as the swirl on top.

The custard is also started on the stove top. Milk and heavy whipping cream are whisked with vanilla and spices (I chose cinnamon and cardamom to give the custard a rich, earthy flavor) over low heat. Egg yolks, corn starch, and sugar were whisked separately before the two mixtures were combined. The trick to combining these mixtures is to pour a little of the hot milk mixture into the egg mixture and thoroughly incorporate before mixing everything together entirely. If the eggs and hot milk are mixed together immediately without this process, the eggs will cook and the entire custard will curdle. It's pretty gross-looking, and doesn't taste good.

The rhubarb compote is thicker than the custard before cooking. I chose to layer a few ladles of rhubarb compote at the bottom of each tart, but I also wanted to achieve the swirl seen in the photos. I determined that I needed to cook the tart 30 minutes (until starting to set) before adding the rhubarb swirl on top. When I tried adding the swirl earlier, it just sank through to the bottom.

There were a few things I could certainly improve upon. To begin with, my rhubarb swirl looks awful. If I had thought it through, I would have chosen to use a pastry bag to form the swirl; this would have provided a much more consistent thickness and better control of the design. Also, I accidentally under-baked my crust a little bit. I did not do the second round of blind baking (without the beans) quite long enough, because I was a little afraid of the color I was getting. While the bottom of my tart is not quite soggy, it is a little soft. I have accounted for this mistake in the baking times I am giving in the directions.

Next up, I will share my rather successful attempt at making a fruity cake for Series 8, Episode 1's signature bake!

Instructions

Ingredients

For the pastry crust:

1 1/4 C all purpose flour

1/2 C (1 stick) cold butter, unsalted

1/2 tsp salt

1/4 C granulated sugar

1/4 C whole milk

For the rhubarb compote:

3/4 lb rhubarb, thinly sliced

1/4 C granulated sugar

2 tbsp water

2 drops red food coloring

For the custard:

250 mL whole milk

250 mL heavy whipping cream

1/2 tbsp ground cardamom

1 tsp ground cinnamon

1/2 tbsp vanilla extract

100g granulated sugar

8 egg yolks

1 tsp corn starch

Directions

1. Preheat oven to 350°F (180°C). 
2. Mix pastry crust together. Mix salt, sugar, and flour together. Cut the cold butter in using fingers or a food processor until the mixture forms small crumbs. Add cold milk until the dough just barely comes together. Form into a ball.
3. Lightly flour a work surface and a rolling pin. Roll out dough to 3mm thickness. Drape in tart tin and cut off the outer excess of the dough. Form some of this leftover dough into a ball and use it to press the crust dough into the corners and creases of the tart tin. Fill with baking beans, on parchment paper. Bake 20 minutes. 
4. Remove crust from oven, and remove baking beans. Cut off remaining excess crust. Return to oven a further 20 minutes. Remove and let cool while making the rhubarb compote and custard mix.
5. To make the rhubarb compote, mix sliced rhubarb, sugar, and water in a saucepan. Bring to a simmer over low heat, 20 minutes or until mushy. Add food coloring and put mixture in a blender or food processor. Pureé until smooth.
6. To make the custard, mix milk, whipping cream, cardamom, cinnamon, and vanilla extract in a saucepan. Bring over low-medium heat to warm the mixture to a near simmer. Meanwhile, mix together egg yolks (you can save the whites for all sorts of other bakes, or for egg white omelets), sugar, and corn starch in a separate bowl. Once the milk mixture is hot, ladle 2-3 ladles of it into the egg yolk mixture, mixing continuously. Return the egg mixture with the little bit of milk back into the milk mixture, and fully incorporate. Take off the heat.
7. To prepare the tart, put a fine layer of rhubarb compote in the bottom of the blind-baked crust. Reserve 1/4 of the rhubarb compote in a piping bag for the decoration. Then carefully pour the custard on top of the rhubarb compote, filling the crust until about 1/8" below the edge.*
8. Bake the tart 30 minutes. Remove the tart from the oven, and use a piping bag to decorate the top of the tart with the reserved rhubarb compote. Return the tart to the oven and bake 10 more minutes.
9. Remove the tart from the oven and let cool to room temperature. Cool in the oven at least 2 hours before serving.