Ginger Bombe (Bombe au Gingembre)

Ingredients

• 1 pint (570 ml) whole milk (Full-fat milk gives the richest custard)
• 2 lemons' worth lemon peel (Use a vegetable peeler to remove only the yellow peel, avoiding the bitter white pith)
• 3 oz (85 g) caster sugar (For the custard base)
• 4 large egg yolks (Separated from whites; whites can be saved for another use)
• 0.25 tsp (approximately — enough to cover a small coin) ground ginger (A threepenny piece was roughly the size of a modern 5p coin; about ¼ tsp ground ginger is a reliable modern equivalent)
• 2 lemons' worth (approx. 60 ml / 4 tbsp) lemon juice, strained (Juice from the same 2 lemons used for the peel; strain out all pips and pulp)
• 6 drops vanilla essence (Use a good-quality vanilla essence or extract; 6 drops is approximately ⅛ tsp)
• 0.5 pint (285 ml) whipping cream (Whip to soft peaks before use; do this just before you need to fold it in)
• 0.5 oz (15 g) caster sugar (For sweetening the whipped cream)
• 3 oz (85 g) preserved ginger (stem ginger in syrup) (Drained from its syrup before dicing)
• 1 tbsp (approx. — 'a little') maraschino liqueur (Just enough to coat and flavour the diced ginger; do not soak)

Instructions

1. 1Pour the pint (570 ml) of whole milk into a medium, heavy-bottomed saucepan. Add the peel of 2 lemons (removed with a vegetable peeler in wide strips, avoiding the white pith) and 3 oz (85 g) of caster sugar. Place the pan over medium heat and stir gently until the sugar dissolves. Continue heating, stirring occasionally, until the milk just comes to a boil — you will see small bubbles rapidly breaking the surface. Remove from the heat immediately. This infusion gives the custard its lemon flavour.
2. 2While the milk heats in step 1, place the 4 egg yolks and the ground ginger (approximately ¼ tsp — enough to cover a small coin) into a large heatproof bowl. Whisk them together well until the mixture is smooth and slightly paler in colour. Once the milk has come to a boil (step 1), you must temper the eggs to prevent scrambling: slowly pour the hot milk in a thin, steady stream into the egg yolk mixture, whisking constantly and vigorously the entire time. Pour gradually — do not dump all the milk in at once. This gradual addition raises the temperature of the yolks gently. Once all the milk has been incorporated, your custard mixture is ready to thicken.
3. 3Pour the combined egg and milk mixture back into the saucepan. Set it over low-to-medium heat. Stir constantly with a wooden spoon or silicone spatula, making sure to reach the bottom and edges of the pan. The custard is ready when it thickens enough to coat the back of the spoon — run your finger across the back of the spoon; if the line holds without the custard running back over it, it is done. Do not let it boil or it will curdle. This typically takes 8–12 minutes on low heat. Immediately remove from heat. Now strain ('tammy') the custard: pour it through a fine-mesh sieve into a clean bowl, pressing gently. This removes the lemon peel and any bits of cooked egg, leaving a silky smooth custard.
4. 4Into the strained, hot custard (now in the clean bowl), stir in the strained juice of the 2 lemons (approximately 4 tbsp / 60 ml) and 6 drops of vanilla essence. Stir well to combine. Place the bowl over a larger bowl filled with ice and cold water (an ice bath) to speed up cooling, stirring occasionally, until the custard is completely cold. Alternatively, leave it uncovered to cool at room temperature, then refrigerate until fully cold — about 1 hour. The custard must be completely cold before freezing.
5. 5Pour the cold custard into your ice cream machine and churn according to the manufacturer's instructions, until it reaches a thick, part-frozen consistency — similar to a very thick soft-serve or a semifreddo consistency. It should hold its shape when scooped but not be fully firm. If you do not have an ice cream machine, pour the custard into a shallow freezer-safe container, freeze for 45 minutes, then scrape and stir vigorously with a fork to break up ice crystals. Repeat this every 30 minutes until you reach the same thick, part-frozen consistency (approximately 2–3 cycles). The custard must be part-frozen before you add the cream and mould it.
6. 6Just before the custard reaches the part-frozen stage, whip the half pint (285 ml) of whipping cream with the half ounce (15 g) of caster sugar until soft peaks form — the cream should hold a gentle peak when the whisk is lifted but not be stiff or grainy. When the custard is part-frozen, remove it from the machine (or freezer container) and transfer it to a large bowl. Gently fold the sweetened whipped cream into the part-frozen custard using a large spatula, cutting and folding rather than stirring, until just combined. This keeps the mixture light and airy.
7. 7While the cream is being whipped (or just before assembling the bombe), drain the 3 oz (85 g) of preserved ginger from its syrup. Cut the ginger pieces into small dice shapes — aim for approximately 1 cm cubes. Place the diced ginger in a small bowl and drizzle over approximately 1 tablespoon of maraschino liqueur. Stir gently to coat all the pieces. Set aside. This will form the flavourful centre of the bombe.
8. 8Place a 1-litre (approximately) bombe mould, pudding basin, or round-bottomed metal bowl in the freezer for 5 minutes to chill it. Remove it from the freezer. Using a large spoon or spatula, spoon the cream-and-custard mixture into the mould, pressing it firmly against the sides and base to create an even layer approximately 3–4 cm thick all the way around, leaving a well (a hollow space) in the centre. Work quickly so the mixture does not melt. Spoon all of the maraschino-flavoured diced preserved ginger into this hollow centre well. Then spoon the remaining cream-and-custard mixture over the top of the ginger to fill and seal the mould completely. Smooth the surface flat with the back of a spoon. If your mould has a lid, press it on firmly. If not, cover tightly with cling film pressed directly onto the surface.
9. 9Place the filled and covered mould in the freezer. Freeze for 3½ hours (210 minutes) until completely firm and solid all the way through. Do not disturb it during this time. The long freeze ensures the bombe holds its domed shape when unmoulded.
10. 10Remove the bombe from the freezer. If using a lidded metal mould, remove the lid. To unmould, fill a large bowl or your sink with hot (not boiling) water. Briefly dip the outside of the mould into the hot water for 5–8 seconds only — do not submerge it for longer or the ice cream will melt. Remove from the water, place a chilled serving plate upside-down over the top of the mould, then quickly and confidently flip both the mould and plate over together so the plate is now on the bottom. Give a gentle shake — the bombe should drop onto the plate. If it does not release, dip again briefly in the hot water and try once more. If you used cling film, peel it away. The bombe should sit as a neat dome on the plate. Place a folded cloth napkin or a decorative doily on the serving plate around the base to present it elegantly, as was traditional. Serve immediately at the table, slicing into wedges for each guest.