Semifreddo sits between ice cream and mousse in texture, and this maple walnut version is one you can make ahead. A maple-sweetened custard is folded into whipped cream, studded with toasted walnuts, and frozen until firm enough to slice. Finished with buttery caramel sauce, it tastes cool, creamy, and nutty. The steps are simple, but a few of them decide whether the loaf turns out light and clean-cutting.
Cooking the Custard Gently
Egg yolks are the foundation here, and they need patience. Set the heatproof bowl over simmering water, keeping its base above the water rather than sitting in it, so the yolks thicken without scrambling. Whisk constantly until the custard turns thick and pale. Once it comes off the heat, whisk in the vanilla bean paste and let it cool until barely warm. Hot custard would deflate the whipped cream and cost you the airy texture.
Whipping, Folding, and Freezing
Keep the cream cold and chill the bowl before whipping, since cold cream builds stiff peaks more reliably. Toast the walnuts until fragrant and slightly darker, then chop part of them and save the nicest halves for garnish. Stop whipping when the peaks stand firm, because overwhipped cream turns grainy and folds poorly. Fold the cooled custard in gradually with a rubber spatula, then add the chopped walnuts so they spread evenly through the mixture.
Line the loaf pan with plastic wrap, leaving generous overhang on the long sides so you can lift the frozen loaf out cleanly. Spoon in the mixture, smooth the top, and freeze until it is firm all the way through. A fully frozen loaf slices cleanly, so resist the urge to cut it early.
Caramel Sauce and Serving
Caramel rewards your full attention. Leave the sugar undisturbed until its edges melt, then swirl the pan gently until the sugar turns deep amber. Take the pan off the heat before adding the cream, and pour it in slowly, since the mixture will bubble and steam. Whisk in the butter and kosher salt until smooth.
For clean slices, dip a sharp knife in hot water and wipe it dry between cuts. Spoon the caramel over the slices and scatter the reserved toasted walnut halves on top for crunch.
Frequently Asked Questions
Why does the custard need to sit over simmering water?
Gentle heat from the simmering water thickens the egg yolks into a smooth custard without scrambling them. Keep the bowl above the water rather than in it, and whisk constantly. The custard is ready when it is thick, pale, and has reached the target temperature on an instant-read thermometer.
How do I keep the caramel sauce from spattering?
Remove the pan from the heat before adding the cream, then pour it in slowly. The mixture will bubble and steam, so whisk steadily. If sugar lumps remain, return the pan to low heat briefly and whisk until smooth. Let the sauce cool slightly so it thickens before serving.
Why does my semifreddo crumble when I slice it?
Crumbling usually means the loaf is not yet frozen solid. Semifreddo slices cleanly only when it is firm all the way through, so give it more freezer time. If it still feels too hard to cut after its rest, let it stand at room temperature briefly, then slice with a hot, dry knife.
Maple Walnut Semifreddo with Caramel Sauce
Course: DessertCuisine: AmericanDifficulty: Medium8
servings15
minutes20
minutes360
kcal6
hours55
minutesA chilled, frozen loaf of maple-sweetened custard folded into whipped cream with toasted walnuts, sliced and served with a buttery caramel sauce. It is a make-ahead dessert that slices cleanly once fully frozen.
Ingredients
- Semifreddo
1/2 cup walnut halves or pieces (about 2 oz)
3 large egg yolks
1/3 cup pure maple syrup
1/8 tsp fine sea salt
1 tsp vanilla bean paste
1 1/2 cups cold heavy cream
- Caramel sauce
1/2 cup granulated sugar
1/3 cup heavy cream
2 tbsp unsalted butter, cut into pieces
1/4 tsp kosher salt
- Garnish
2 tbsp walnut halves, toasted
Directions
- Semifreddo
- Heat the oven to 350°F with a rack in the center. Spread the 1/2 cup walnuts and the 2 tablespoons garnish walnut halves on a rimmed baking sheet and toast for 8 minutes, stirring once halfway, until fragrant and slightly darker. Transfer the garnish walnut halves to a plate to cool. Let the 1/2 cup walnuts cool, then chop coarsely.
- Line a 9×5-inch loaf pan with plastic wrap, leaving a 2-inch overhang on the long sides. Keep the cream in the refrigerator until you are ready to whip it.
- Fill a medium saucepan with about 1 inch of water and bring it to a gentle simmer over medium-low heat. In a heatproof bowl that sits over the pan without touching the water, whisk the egg yolks, maple syrup and fine sea salt. Whisk constantly for 6 minutes, until the mixture is thick, pale and reaches 160°F on an instant-read thermometer.
- Remove the bowl from the heat and whisk in the vanilla bean paste. Let the custard cool for 15 minutes, whisking occasionally, until it is barely warm.
- While the custard cools, beat the cold heavy cream in a chilled bowl with a mixer on medium-high speed until it holds stiff peaks, about 3 to 4 minutes.
- Fold the cooled custard into the whipped cream in three additions with a rubber spatula, keeping the mixture airy. Fold in the 1/2 cup toasted, chopped walnuts until evenly distributed.
- Spoon the mixture into the prepared loaf pan and smooth the top. Fold the plastic wrap over the top and freeze until firm, at least 6 hours or overnight.
- Caramel sauce
- Make the caramel just before serving. Heat the 1/2 cup sugar in a small saucepan over medium heat. Leave it undisturbed until the edges melt, then gently swirl the pan as the sugar melts and turns deep amber, about 5 to 6 minutes total.
- Remove the pan from the heat. Carefully whisk in the 1/3 cup heavy cream, which will bubble and steam. Whisk in the butter pieces and kosher salt until smooth. If any sugar lumps remain, return the pan to low heat for about 1 minute and whisk until smooth. Let the sauce cool slightly so it thickens.
- Serving
- Run a thin knife around the edges of the pan, then lift the plastic wrap to release the frozen loaf onto a cutting board. Peel off the plastic and let the loaf stand at room temperature for 5 minutes.
- Dip a sharp knife in hot water, wipe it dry, and cut the semifreddo into 1-inch-thick slices. Arrange the slices on a serving plate, spoon the caramel sauce over them and scatter the 2 tablespoons toasted walnut halves set aside earlier on top.
Notes
- Cooking the yolks over simmering water until they reach 160°F heats them enough to be safe to eat without baking. Keep the bowl above the water rather than in it so the yolks cook gently and do not scramble.
- Add the cream to the hot caramel slowly and off the heat. The mixture will bubble vigorously, and adding it gradually keeps the sauce from spattering.
- Semifreddo slices cleanly when it is fully frozen. If the loaf is still too firm to cut after its 5-minute rest, let it stand at room temperature for a few more minutes before slicing.
- Leftover caramel sauce keeps in a covered container in the refrigerator for up to 1 week. Rewarm it gently over low heat, adding a teaspoon of cream if it has thickened too much.
