Chestnut & Blueberry tartelette

Required recipes

• Chocolate tart shell

• Chocolate marquise

It's recommended to have the tart shells ready before starting this recipe. They can be prepared even 1 week in advance and kept at room temperature in an airtight container. Chocolate marquise can be prepared 1 day in advance and kept at room temperature in an airtight container. Place a sheet of paper towel in the container to help regulate humidity.

Equipment

• Tart ring. Here I'm using DeBuyer round ring tart ⌀ 6.5 cm

• Hemisphere mold. Here I'm using Silikomart Semisfera ⌀ 4cm

---

Day 1

Blueberry gel and whipped ganache

250g Frozen berries - Fresh berries are the best option when they are available.

25g Caster sugar

1 vanilla pod

1. Put the frozen berries into a pot together with the sugar and the vanilla pod (scrape the seeds and use both them and the pod) and cover with kitchen film so that the pot is properly sealed. This will allow to keep the moist, avoiding the liquid to evaporate.

2. Cook in water bath at low heat for around 1 hour to extract the juice and soften the berries.

3. Remove from the heat and blend with a hand blender till smooth, then filter with a sieve to get the juice with the pulp together. You're going to use it in the gel and ganache preparation described below (the ingredient is reported as blueberry pulp there).

Blueberry gel

100g Blueberry pulp - When preparing this gel, do not combine with agar agar all the pulp. Keep always some to simplify the blending process.

2g Agar agar

1. In a small pot warm up the blueberry pulp.

2. When it starts to simmer gradually add the agar agar and stir for 1 minute.

3. Remove from the heat and let it rest in the fridge in a container covered with kitchen film.

4. Once the juice has set, cut it in small pieces and blend with a hand blender till smooth. Add some extra berries pulp for a smoother texture. If you exceed in adding the juice, you can balance with some xanthan gum.

5. Filter through a sieve to remove eventual lumps.

Blueberry whipped ganache

You can follow the recipe described here. Once the ganache is ready, whip it and pour into a hemisphere mold. I'm using Silikomart Semisfera ⌀ 4cm. Place the mold in the freezer and allow the ganache to freeze for a minimum of 3 hours.

Chestnut paste and whipped ganache

The process outlined uses pre-cooked chestnuts, which is the simplest option since it eliminates the need to cook and peel them. Additionally, finding high-quality chestnuts can be challenging, and some may need to be discarded. Pre-cooked chestnuts eliminate this risk. However, if you are confident in the quality of the fresh chestnuts available, you can prepare them yourself. To do so, make an 'X' cut on each chestnut (to prevent them from bursting) and roast them in the oven at 200°C for 15 minutes. Then, peel them and boil in water for around 20 minutes.

Chestnut paste

150g Pre-cooked chestnut

q.s. Whole milk (e.g. 200g)

The recipe does not specify an exact amount of milk because the goal is to soften the chestnuts and blend them into a paste. If your chestnuts are already soft, you can simply blend them with milk. However, if they are not soft, you can boil them in the milk. When blending, gradually add milk until you achieve the desired texture. Ideally, you want a paste that is not too runny.

Chestnut whipped ganache

90g Heavy cream 35% fat (1)

40g Whole milk

90g Chestnut paste

2 Platinum gelatine sheets (250 bloom, 1 sheet = 1,75 g) 

100g Finely chopped white chocolate

210g Cold heavy cream 35% fat (2)

1. Place the gelatine sheet in a bowl of cold water and let it soak for 5-10 minutes, or until it becomes soft and pliable.

2. In a small saucepan, combine the heavy cream (1) and the whole milk. Heat over low heat, stirring occasionally, until the mixture begins to simmer gently (do not boil). Then remove from the heat.

3. Squeeze the excess water from the softened gelatine and add it to the hot cream mixture. Add the finely chopped white chocolate and stir gently until both the gelatine and chocolate are completely melted. You can also use a hand blender to get a smoother and more uniform result.

4. Add the chestnut paste and gradually pour in the cold heavy cream (2). Blend with a hand blender until combined. Be careful not to overblend (you don't need to emulsify at this stage).

5. Pour the mixture into a container, cover it, and refrigerate for at least 6 hours, or preferably overnight, to allow it to set completely.

---

Day 2

Assembly

1. Whip the chestnut ganache until it forms medium peaks. This means the mixture will hold its shape when the beaters are lifted, and the peaks will gently fold over. Transfer it to a piping bag and keep it in the fridge.

2. Pour a thin layer of chestnut paste on the bottom of the tart shell for a more intense chestnut flavour.

3. Add some blueberry puree. You can even add some blueberries cutted in half. Don't limit yourself and your creativity!

4. Put a marquise disc into the tart and press gently. Cover with some additional chestnut paste and adjust the level with a spatula so that it evenly fills the tart to the top.

5. Place a blueberry whipped ganache dome on top, then pipe the chestnut whipped ganache that was kept in the fridge. To achieve the spiral effect, cut the tip of the piping bag at an angle of approximately 40° from the edge of the piping bag, as shown in the figure below. Naturally, the size of the tip you cut off will affect the detail of the pattern. You can view this reel to better understand how I achieved the effect shown in the photos.

6. Optionally add golden leaves / flakes. In my case I'm also adding an extra decoration on top. You can replace it with a fresh blueberry.