Step 1Heat the oven to 350 degrees. Squeeze the spinach, pressing out as much excess water as possible (wring the spinach out in a towel if possible).
Step 2In a large bowl, combine the spinach, cream cheese, feta, onion, dill, 1/4 cup olive oil and seasoning, kneading the mixture using your hands until all of the ingredients are evenly combined.
Step 3Place one sheet of phyllo down horizontally. Brush lightly with olive oil. Place a second sheet of phyllo dough directly over the first. Brush with olive oil. (Keep the remaining sheets of phyllo covered under a damp towel so they don't dry out.)
Step 4Add roughly one rounded teaspoon of the spinach mixture to the phyllo, spacing the dollops a couple of inches apart (you should be able to fit 5 mounds of the spinach mixture on one edge of each wider [horizontal] sheet of phyllo).
Step 5Cut the phyllo vertically in between each dollop of spinach mixture. Fold one corner of each strip into a triangle, covering the filling. Continue to fold, as if folding a flag, retaining the triangular shape until you reach the edge of the strip. Place the spanakopita on a baking sheet and brush the tops lightly with oil. Continue until all of the spanakopita are formed. (The spanakopita can be frozen at this time and saved until ready to bake. Cover the baking sheets tightly with plastic wrap. Note that the spanakopita will take a little longer to bake from a frozen state.)
Step 6Bake the spanakopita, 1 sheet at a time, until the phyllo is crisp and lightly golden, about 25 minutes. Serve with Greek yogurt.