Add sliced strawberries, sugar and lemon juice to a medium bowl and toss. Mash the berries well or pulse in a food processor until smooth with some lumps or small pieces here and there.: The bowl will start smelling bright and fruity, and you should hear a soft glug of syrup as the 1/3 c sugar draws juice from the strawberries . Let the mixture sit for several minutes so the sugar can macerate the fruit, which concentrates flavor and produces a glossy syrup. I press a few slices against the bowl with a fork to encourage juice release while keeping some chunk integrity for texture. A common mistake is skipping the rest time, which results in less flavorful strawberries and a drier ice cream.
In another bowl, beat the heavy whipping cream on medium high until stiff peaks start to form. In a separate bowl, add the condensed milk, vanilla and sea salt (if desired) and stir to combine.: When you mash, the aroma will intensify and the color deepens to a vivid pink. Use a fork or pulse briefly in the food processor; I prefer a mix of smooth puree and small bits because those bits give satisfying fruit bites. Avoid over processing into complete purée unless you want a uniformly smooth texture, since too much processing can remove the lively bits that make each scoop interesting.
Gently fold the whipped cream into the condensed milk mixture trying to keep the whipped cream from losing its fullness. Gently stir in the strawberry mixture. Transfer the mixture to a freezer safe container and freeze for at least 4 hours or until frozen.: As you beat, listen for the change from a gentle whoosh to a firmer, more urgent beat, and watch the cream thicken and hold shape. The texture should be fluffy and billowy, with peaks that stand up when you lift the whisk. Under whipping leaves the base too loose and results in a denser final texture, while over whipping can turn the cream grainy or toward butter.
Allow to sit out for about 10 minutes for easier scooping and enjoy!: The condensed milk mixture should be glossy and viscous, releasing a warm caramel like scent. Mixing the vanilla extract and optional pinch of sea salt evenly ensures flavor balance throughout. If the condensed milk feels lumpy or grainy, stir until smooth; lumps can create uneven sweetness and texture.
Gently fold the whipped cream into the condensed milk mixture trying to keep the whipped cream from losing its fullness: You will feel resistance as you fold, the airy whipped cream slowly blending into the dense condensed milk. Use a large spatula in sweeping motions from bottom to top to retain as much air as possible. The goal is a homogenous pale pink base that still feels light. Rushing or stirring vigorously knocks out air and yields a heavier, less scoopable result.
Gently stir in the strawberry mixture: The mixed base will blush with streaks of ruby from the strawberries and smell fruity and sweet. Fold the berry purée in with gentle turns to create swirls or full incorporation depending on your preference. Watch for visual cues, like even distribution of the berry color, and avoid aggressive mixing which flattens the aeration and can lead to icy texture after freezing.
Transfer the mixture to a freezer safe container and freeze for at least 4 hours or until frozen: Pouring the mixture into a shallow, wide container helps it freeze more evenly, and you will hear a soft pour and see the surface settle flat. Place a piece of plastic wrap directly on the surface to minimize ice crystals, then cover with a lid. Freeze for at least 4 hours; if it seems too soft after that time, allow extra chilling. A frequent error is using a deep container which slows freezing and increases the chance of large ice crystals forming.
Allow to sit out for about 10 minutes for easier scooping and enjoy: After removing from the freezer, the surface will glisten and the aroma of strawberries will be more pronounced. Letting the container rest at room temperature for about 10 minutes softens the edges just enough to make clean scoops without melting. Scooping straight from very hard ice cream tears at texture and makes it seem denser, so patience here pays off for smooth, scoopable servings.
