Pickled Feta and Cerignola Olives with Strawberries

Name: Pickled Feta and Cerignola Olives with Strawberries
Ingredients: 3 cups Champagne vinegar or white balsamic vinegar; 1/2 cup granulated sugar; 2 tablespoons coriander seeds; 2 tablespoons mustard seeds; 1 medium shallot, sliced; 4 whole garlic cloves; 4 sprigs cilantro; 2 pounds feta, diced or crumbled (roughly 6 1/2 cups); 1 pound Cerignola olives (red, green, or black), pitted and cut in half; 1 pound fresh strawberries, hulled and cut in quarters; 1/4 cup extra-virgin olive oil; 1/4 cup cilantro, chopped; 12 ounces baby spinach; Salt and white pepper