Whisk the eggs, milk, blood orange juice, blood orange zest, vanilla extract, and cinnamon in a mixing bowl until fully combined.
Place the brioche slices in a shallow dish and pour the egg mixture over them. Let the slices soak for 2 minutes on each side.
Heat a large skillet over medium heat and add 1 tablespoon of butter. Swirl to coat the pan.
Cook 4 brioche slices at a time for 3 to 4 minutes per side until golden brown. Add the remaining butter before cooking the second batch.
Serve the French toast warm with blood orange slices and pomegranate seeds scattered on top.