Soften the cream cheese. Leave it out for 30 to 45 minutes.
It should be pliable and slightly cool, not cold and firm. This step is key for a smooth texture.
Beat the cream cheese. In a medium bowl, use a hand mixer on medium speed (or a whisk and some elbow grease) to beat until completely smooth, about 1 to 2 minutes. Scrape the bowl.
Stream in the condensed milk. With the mixer on low, gradually add the sweetened condensed milk.
Mix until the mixture looks glossy and unified, about 1 minute. Don’t overbeat.
Add lemon juice to taste. Start with 2 tablespoons. Mix just until combined, then taste.
For a brighter tang and slightly firmer set, add up to 1 tablespoon more. Avoid adding more than 3 tablespoons or the texture may loosen.
Prepare your cups. Line up 6 to 8 small cups, jars, or ramekins. If using a crumb base, you can simply sprinkle crumbs in the bottom or make a quick crust by mixing 1 cup crumbs with 2 tablespoons melted butter and pressing a thin layer into each cup.
Fill the cups. Spoon or pipe the cheesecake mixture evenly into the cups, smoothing the tops with the back of a spoon.
You’ll get about 6 generous servings or 8 smaller ones.
Chill to set. Cover and refrigerate for at least 1 to 2 hours. They’ll thicken as they chill and taste even better after 4 hours. For the cleanest texture, chill overnight.
Top and serve. Add berries, a spoonful of jam, lemon zest, or chocolate shavings right before serving.
Keep extras chilled until ready to eat.