Begin by opening a can of high-quality sardines packed in olive oil. Gently remove any bones you find using your fingers or a fork, being careful not to break the flesh. Place the cleaned sardines in a medium mixing bowl, ensuring the oily liquid from the can is also added for extra flavor.

Using a fork, mash the sardines into a smooth, paste-like consistency. Take your time as you work to break down the sardines thoroughly, aiming for a creamy texture that may have some small chunks for added interest.

Add Greek yogurt, softened unsalted butter, chopped capers, minced chives, fresh dill, lemon zest, and lemon juice to the mashed sardines. Sprinkle in kosher salt and freshly ground black pepper to taste. Mix everything together with a spatula until well combined.

Transfer the sardine rillettes mixture into an airtight container, smoothing the top with a spatula for an even surface. Cover tightly and refrigerate for at least 1 hour.

When ready to serve, take the sardine rillettes out of the fridge and let it sit at room temperature for about 15 minutes. Serve alongside crispy baguette slices, crackers, or fresh vegetable sticks.