1/2 pound strawberries, hulled
1 cup apple cider or white wine vinegar
1/2 cup granulated sugar
1/4 cup water
1 teaspoon kosher salt
1/2 teaspoon black peppercorns
3 sprigs fresh thyme
1/4 teaspoon red pepper flakes
Place the strawberries in a glass jar. Set aside.
Combine the vinegar, sugar, water, salt, peppercorns, thyme, and red pepper flakes in a medium saucepan. Bring to a boil over medium heat, stirring to dissolve the sugar.
Reduce the heat to low and simmer for 5 minutes.
Remove the pan from the heat and allow it to cool slightly.
Pour the pickling liquid over the strawberries.
Let cool to room temperature, then cover and refrigerate.
The strawberries will be ready to eat in 24 hours but will continue to develop flavor for up to 2 weeks.