Custard-style (also known as French-style) ice cream contains egg yolks, which gives it a smoother, richer mouthfeel than traditional ice cream (also known as Philadelphia-style), which is comprised of only cream, milk, sugar and flavorings. Although it is a bit trickier to make, it’s much more forgiving to the imperfect conditions of home ice cream making. Plus, I prefer the richer flavor and texture that the egg yolks provide.
A custard is a food prepared using egg yolks and cream or milk. (Other examples of custards include creme brulee, flan, creme anglaise, and pastry cream.) For this type of ice cream, you first make a thin custard. Flavor can be introduced to the custard base at three different stages, and in this recipe, we take advantage of them all!
Flavor stage 1:
The first way is to infuse warm cream with flavor. It’s exactly the same concept as steeping tea, but instead of water, we’re using cream, and instead of tea, we’re using basil. The cream is an excellent medium for this because it contains both fat and water components, so the cream can soak up any fat-soluble flavor molecules as well as any water-soluble flavor molecules. That means we’re getting the fullest bouquet of flavors possible!
Flavor stage 2:
The second way is by adding a flavorful ingredient. This is typically something other than the dairy, egg and sugar components of a standard custard. Common examples are chocolate, flavor extracts, liqueurs or fruit purees. In this recipe, we’re adding both vanilla extract and a homemade strawberry syrup!
Flavor stage 3:
The third way to introduce flavor to your custard base is to add solid bits, known in the ice cream industry as inclusions. Some common examples are chocolate chips, cookie bits, nuts, fruits, raisins, and a variety of “swirls”. In this recipe, we’re adding homemade stewed strawberries, which are designed to be only semi-solid when frozen. That prevents you from biting into a rock-hard frozen strawberry.
Freezing & Churning
Once the custard is complete, that’s when the magic of ice cream truly comes out–the freezing stage! If all of your fat:sugar:egg:water:flavor ratios are right, then your ice cream will freeze perfectly! It all starts in your ice cream maker. Whether you’ve got an electric model, like me, or if you’re cranking it by hand, the concepts are the same. You put your liquid custard into an super-chilled canister and churn constantly as it’s freezing. The constant churning serves a couple of purposes: (1) it keeps the temperature of your custard even and it keeps the tiny ice crystals in constant motion as they freeze. Ice crystals in ice cream begin microscopically small, but as they sit, they attract neighboring water molecules and the crystals grow in size. Keeping them in motion prevents them from being able to grab onto their neighbors, which means they stay small, which means smooth ice cream for you! Ice crystals that grow big enough for your tongue to detect feel like sand in your mouth (ew). Rapid freezing also helps keep crystals small. (2) The other purpose of the constant churning is to fold air into your ice cream. Air that has been incorporated into an ice cream base is known as overrun. As your ice cream freezes, it gets more and more solid, which allows it to support more and more tiny air pockets within its structure. These air pockets are what give ice cream its unique texture and meltability. Ice cream is actually a frozen foam!
The final stage is called hardening. When your ice cream comes out of your ice cream machine, about 40% of the water in your ice cream is still liquid (that’s why it looks like soft serve). After you pull the soft ice cream out of the machine, you put it into a container to sit in a freezer overnight. This is when that remaining 40% turns into ice crystals. This is also where a lot of homemade ice cream recipes have trouble! If you have too much water in your mix, then your beautiful soft serve will freeze into a solid brick during the hardening stage! Other ingredients like fat, sugar, dairy solids, and even air inhibit water’s ability to freeze into large crystals. Fat stays soft even at freezing temperatures. Sugar and dairy solids join with some of the water molecules and reduce their freezing point (so they stay liquid). If you strike the right balance, you’ll get lots of teeny tiny ice particles mixed with lots of soft or liquid particles. This combination is what gives you a delightfully smooth, scoopable, yet frozen, treat! I’ve calculated the ratios in the recipe below to ensure that the fat:sugar:egg:water:flavor ratios are where they should be, so you’ll end up with a perfectly scoopable ice cream in the end!
2 cups heavy cream, divided (484 g)
1 cup skim milk (234 g)
1/2 cup sugar, granulated (106 g)
1/8 tsp salt (2 g)
1 cup basil, fresh, lightly packed
7 egg yolks (from large eggs) (119 g)
2 tsp vanilla extract (10 g)
1 cup (approx) strawberry syrup (from strawberry compote) (216 g)
1 cup (approx) stewed strawberries, diced and frozen (from strawberry compote)
Candied basil, for garnish
1. In a medium saucepan, mix 1 cup cream with milk, sugar, and salt. Warm over med-high heat, stirring occasionally, until sugar and salt are completely dissolved and tiny bubbles begin to form around the edge of the pan (do not boil).
2. Stir in fresh basil and remove from heat. Cover and let stand for 1 hour.
3. Pour the remaining cup of cream into a large bowl. Place that bowl into an ice water bath and place a fine mesh strainer on top.
4. In a separate medium bowl, whisk egg yolk lightly. Set aside.
5. Put your saucepan of cream and basil back on the stove over med-high heat until bubbles form around the edges (do not boil).
6. Whisking constantly, drizzle half of the heated cream into the egg yolks. (To keep the egg yolks from scrambling, you want to warm them slowly and evenly.)
7. Now pour the warmed egg yolk mixture back into the saucepan with the remaining cream mixture and heat over med-low heat, stirring constantly, until it thickens. (You’re making a custard now!) Your custard is thick enough when it coats the back of your rubber spatula (or wooden spoon) and will hold a line when you draw your finger through it. Do not allow the mixture to boil!
8. Strain the custard through the fine metal strainer and into the bowl of cream that’s been chilling in the ice water bath. Give the basil a little squeeze with your rubber spatula to get as much of the custard through as possible. Discard used basil.
9. Allow the custard to chill in the water ice bath until it feels cool to the touch, then stir in the strawberry syrup and vanilla extract.
10. Cover and refrigerate this mixture until it’s completely chilled (at least 4 hours) or overnight.
11. Freeze the mixture in your ice cream maker according to the manufacturer instructions.
12. Five minutes before the ice cream is done (or when it’s at the soft-serve stage), add your pre-frozen stewed strawberry bits. Watch to make sure your ice cream maker is able to distribute them evenly. (You may want to stir a few times by hand when you take the ice cream out of the machine, just to be sure you don’t end up with any clumps of strawberry bits in your final ice cream.)
13. Transfer the ice cream to an air tight container and allow it to finish hardening in your freezer overnight, or until hardened. If you’re impatient and don’t want to wait until tomorrow to eat your ice cream, try freezing some of your ice cream in single serve-portions. A smaller block of ice cream will be able to harden faster than a large tub!
14. Once it’s ready, serve yourself two heaping scoops and garnish with a pair of candied basil leaves. You deserve it!
Cooking the strawberries in advance with sugar is important because the cooking and the addition of sugar reduce the amount of free (freeze-into-an-ice-cube) water is reduced. Much of it is either evaporated away or joined with sugar to make a syrup (which won’t fully freeze). This means you’ll get soft, chewable strawberry bits and a smooth scoopable ice cream, even after it’s done hardening.