Rinse the strawberries and pat them dry with paper towels. Then, remove the leaves and slice the strawberries.
In a medium mixing bowl, whisk together the sour cream, sweetened condensed milk, Mexican crema, and vanilla. Give the mixture a taste. If you'd like it sweeter, mix in 1 tablespoon of sweetened condensed milk at a time until it's sweetened to your liking.
In small cups or bowls, alternate adding layers of cream and strawberries, about 3-4 layers each.
Refrigerate the dessert cups for at least 30 minutes before serving to allow the flavors to marry together.
Notes
If you can't find Mexican crema in the refrigerated section of your grocery store, you can use this substitute. Mix 1 tablespoon of lime or lemon juice with 1 cup of heavy cream and let that sit in the fridge for 30 minutes to 2 hours before using.
Store any leftovers in the fridge for up to 2 days in an airtight container. The cream might separate slightly, but it will still be safe to consume.
For a big batch, double or triple the recipe. Chill the crema mixture and then stir in the strawberries. Serve in a large bowl, and use a ladle to spoon the fresas con crema into cups or bowls.