Preheat the oven to 350°F. Lightly grease an 8x4-inch loaf pan.
Combine the flax and water in a small bowl and let sit for 10 minutes.
Add remaining ingredient except cheese and bread and mix well.
Spread the mixture evenly over both sides of the bread slices. Arrange slices in pan so cut sides are facing each other. Distribute cheese shreds between slices and on top of the loaf.
Bake until fragrant, lightly golden brown, and the cheese is melted. Unmold, cut loaf in half down the middle and serve immediately with marinara sauce or your favorite dip.