In a shallow bowl, whisk together the eggs, milk, ground cinnamon, and vanilla extract if using. Continue whisking until the mixture is smooth and evenly combined. Choose a bowl wide enough to dip the bread slices comfortably.
Place each slice of bread into the egg mixture, allowing it to absorb the liquid on both sides. Thick bread works especially well because it develops a tender center while the outside becomes golden. Avoid soaking very soft bread for too long, as it may fall apart during cooking.
Place a large nonstick skillet over medium-low to medium heat. Add the butter and olive oil. Allow the butter to melt and coat the surface of the pan. The combination of butter and olive oil adds flavor while helping prevent the butter from browning too quickly.
Place the soaked bread slices into the warm skillet without overcrowding the pan. Cook for approximately 3–4 minutes on each side, or until the bread becomes golden brown and the egg mixture is fully cooked. Adjust the heat if the bread begins to brown too quickly.
While the French toast cooks, combine the honey, water, cinnamon, and ground ginger in a small saucepan. Warm over low heat for 1–2 minutes, stirring gently until the mixture becomes smooth and pourable. Do not boil the honey mixture vigorously.
Transfer the hot French toast to serving plates. Sprinkle the crumbled feta cheese evenly over each slice. The warmth of the bread will soften the cheese slightly without completely melting it. Add a little lemon zest or freshly ground black pepper for extra flavor, if desired.
Spoon the warm spiced honey syrup over the French toast. Use enough to coat the bread lightly without making it soggy. The sweetness of the honey complements the salty feta, while the cinnamon and ginger add a warm, aromatic flavor.
Finish with fresh thyme or mint leaves. Add chopped pistachios or walnuts for crunch, or serve with fresh figs and strawberries for a fruity touch. Serve immediately while the toast is warm and the edges are crisp.