Wash the cucumber and grate it using a box grater. You can leave the skin on if it's thin, otherwise, peel it.
Once grated, place the cucumber in a clean kitchen towel or cheesecloth and squeeze out as much excess moisture as possible. This step is important to prevent the tzatziki from becoming watery.
Peel and mince the garlic cloves finely and chop the fresh dill finely.
In a mixing bowl, combine the yogurt, grated cucumber, minced garlic, chopped dill, salt, black pepper, vinegar (or lemon juice), and olive oil then Stir the mixture until all the ingredients are well combined.
Taste the tzatziki and adjust the seasoning according to your preference. You can add more salt, pepper, or vinegar if needed.
Cover the bowl with plastic wrap or transfer the tzatziki into an airtight container – try to refrigerate the tzatziki for at least 1 hour before serving. This allows the flavors to meld together and enhances the taste of the sauce.
Garnish with a drizzle of olive oil and a sprinkle of fresh dill before serving, if desired. Serve it as a dip with pita bread, vegetables, or as a condiment for grilled meats or sandwiches.
