refrigerator pickles recipe

#### Ingredients: - **4 cups cucumber slices** (about 4-5 medium cucumbers, sliced into 1/4-inch rounds) - **1 small onion** (thinly sliced, optional) - **1 cup white vinegar** - **1 cup water** - **1/4 cup granulated sugar** - **1 tablespoon salt** (pickling salt or kosher salt works best) - **2 cloves garlic** (sliced) - **1 teaspoon mustard seeds** - **1 teaspoon black peppercorns** - **1/2 teaspoon red pepper flakes** (optional, for a bit of heat) - **Fresh dill sprigs** (optional, for added flavor)