Prep the pan: Line a 8.5 x 4.5-inch loaf pan with parchment and lightly grease the sides. Preheat oven to 350°F (175°C).
Mix dry ingredients: In a large bowl, whisk 2 cups almond flour, 1/2 cup ground golden flaxseed, 1 tablespoon baking powder, and 1/2 teaspoon salt. If using psyllium, add 1 tablespoon.
Blend wet ingredients: In another bowl, whisk 5 large eggs, 2 tablespoons olive oil (or melted butter), 1 teaspoon apple cider vinegar, and 1/2 cup unsweetened almond milk.
Combine: Pour wet into dry and stir until smooth.
The batter should be thick but spreadable—like quick-bread batter. If it’s too thick, add 1–2 tablespoons more almond milk.
Pan and top: Scrape batter into the pan and smooth the top. Sprinkle sesame seeds or everything seasoning if you like.
Bake: Bake 35–45 minutes, until the top is golden and a toothpick comes out clean from the center.
Internal temperature should reach about 200–205°F (93–96°C).
Cool properly: Let the loaf cool in the pan 10 minutes, then transfer to a wire rack. Cool fully before slicing to prevent crumbling.
Slice: Use a sharp serrated knife and cut into 12–14 slices for classic sandwich thickness.