Preheat oven to 350°F. Line a 8x4-inch loaf pan with parchment paper and lightly grease.
Process oats and psyllium husk in a food processor or high-speed blender into fine flour.
In a large bowl, whisk together the processed oat-psyllium husk flour, baking powder, baking soda, and salt. Add eggs, milk, yogurt, melted butter, and honey and whisk until smooth. Let sit for 10 minutes to let the dry ingredients absorb the moisture. The batter will be thick and sticky.
Spoon batter into the prepared loaf pan and smooth the top. Bake for 45–50 minutes, or until the top is golden and a toothpick inserted in the center comes out clean.
Cool in the pan for 15 minutes, then transfer to a wire rack to cool completely before slicing. Store in an airtight container at room temperature for 2 days or in the fridge for up to 5 days.
Notes
For add-ins: Use about 1/3 to 1/2 cup total mix-ins (nuts, seeds, or dried fruit) so the bread doesn’t get too heavy or dense. Stir them in after the batter has rested for 10 minutes, right before transferring to the pan. This keeps the batter from getting too thick too early.
Dairy-free substitutes work well in this recipe. Use a thick dairy-free yogurt, vegan butter, and dairy-free milk.