If using whole bread loaf, use serrated knife to cut bread into 3/4 inch - 1 inch thick slices.
Combine Just Egg, plant milk, syrup (or brown sugar), cinnamon, nutmeg, sea salt, and vanilla in shallow, wide dish. Use wisk or fork to combine custard.
Place sliced bread into dish (typically I can fit about 3-4 slices at a time). Allow bread to soak for about 1 minute. Then flip slices to other side, and soak for 1 more minute.
While soaking second side, heat nonstick pan on low-medium heat. Place 1-1.5 tablespoons of butter in pan. Use spatula to spread melting butter around pan, being careful not to let it burn.
Remove bread from custard, allowing excess custard to drip off. Place in pan.
Cooking on low-medium heat for 2-3 minutes on first side until golden brown, checking after 90 seconds to avoid burning.
Flip to second side. Cook for about 2 additional minutes, checking again after 90 seconds (second side tends to cook more quickly than first).
Remove first batch of French toast from pan. Place in warm oven or microwave, covered, to slow cooling.
Let pan cool enough to wipe with paper towel to remove brown debris. Add more butter and repeat.
Top French Toast with fresh fruit, butter, maple syrup, or other toppings. Enjoy!