Begin by carefully removing the bones from the sardines using your fingers or a small fork. Place the de-boned sardine fillets into a medium mixing bowl.

With a fork, gently mash the sardines in the bowl until they reach a smooth, paste-like consistency.

Add in the Greek yogurt and softened unsalted butter, and then mix in capers, chopped chives, fresh dill, lemon zest, fresh lemon juice, kosher salt, and black pepper. Use a spatula to fold the ingredients together.

Once everything is well combined, cover the bowl tightly and place the mixture in the refrigerator to chill for at least 1 hour.

Before serving, let the Sardine Rillettes come to room temperature for about 15 minutes. Serve it spread on toasted baguette slices or crackers.