Preheat and prep: Heat your oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment, leaving overhang for easy lifting. Lightly grease the sides.

Whisk dry ingredients: In a large bowl, whisk 2 1/2 cups almond flour, 5 tablespoons finely ground psyllium husk powder, 1 tablespoon baking powder, and 1 teaspoon salt until evenly combined and lump-free.

Mix wet ingredients: In a separate bowl or large measuring cup, combine 5 large egg whites, 1 tablespoon apple cider vinegar, 2 tablespoons olive oil (or melted butter), and 1 cup warm water (about 110°F/43°C).

Combine: Pour wet ingredients into dry. Stir with a sturdy spatula until a thick, tacky dough forms. It will firm up as the psyllium absorbs moisture. If it’s crumbly, add warm water 1 tablespoon at a time.

Shape: Transfer dough to the prepared pan. Smooth the top with a damp spatula. For a rustic look, score a shallow line down the center.

Optional toppings: Sprinkle sesame or sunflower seeds on top and press gently to adhere.

Bake: Place on the center rack and bake for 55–65 minutes, until the top is golden and a skewer comes out mostly clean. The loaf should feel set and sound slightly hollow when tapped.

Cool properly: Lift the loaf from the pan and cool on a wire rack for at least 1 hour. Do not slice while hot; it needs time to firm up.

Slice and serve: Use a serrated knife to cut 12–14 slices. Toast to enhance flavor and texture.