In a large bowl, whisk together the eggs, milk, heavy cream, sugar, cinnamon, vanilla extract, orange zest, and salt. Mix until everything looks smooth and fully combined. The custard should smell warm and slightly citrusy.
Cut the tsoureki bread into thick slices, about ¾ to 1 inch thick. Slightly stale bread works best because it absorbs the custard without falling apart. Fresh bread can become too soft during cooking.
Dip each slice into the custard mixture for about 15–20 seconds per side. Make sure the bread absorbs enough liquid but does not become overly soggy. Let the excess custard drip off before cooking.
Place a non-stick skillet or griddle over medium heat and add butter. Allow the butter to melt fully and coat the surface evenly. Medium heat helps the French toast cook through without burning.
Place the soaked slices onto the hot skillet in a single layer. Cook for about 3–4 minutes per side until golden brown and slightly crisp around the edges. The inside should remain soft and fluffy.
Transfer the cooked French toast to serving plates while still warm. Drizzle with maple syrup or honey and top with fresh berries. A light dusting of powdered sugar also looks beautiful.