Step 1

Mix oats and 1 cup buttermilk in a small bowl. Chill overnight to rehydrate oats.

Step 2

Whisk teff flour, flaxseeds, sunflower seeds, almonds, pepitas, walnuts, flaxseed meal, psyllium husks, chia seeds, and salt in a large bowl.

Step 3

Combine maple syrup and 1 cup warm (not hot, ideally about 100°) water in a small bowl. Sprinkle yeast over and let stand until yeast is beginning to foam and smells bready (if it doesn’t foam after 10 minutes, get new yeast). Stir into dry ingredients along with oil and remaining ¼ cup buttermilk. Add rehydrated oats and stir until combined (if using old-fashioned oats, add them along with 1 cup buttermilk).

Step 4

Cover bowl with plastic wrap and let rise in a warm spot until dough has puffed slightly (it won’t rise like non-gluten-free dough, but if you poke your finger into it, it should feel less dense than before) and there may be some subtle cracks across surface of dough, 1¼–1½ hours.

Step 5

Stir dough gently to deflate, then transfer to an 8x5" loaf pan (dough should reach to about the top of pan and this is fine!). Cover with plastic wrap and let dough rise again until domed slightly, 1–1¼ hours.

Step 6

Preheat oven to 350°. Bake bread until top is dark brown and springs back when pressed and an instant-read thermometer inserted into the center registers 190°, 60–75 minutes. Let cool in pan slightly before slicing.

Step 7

Do Ahead: Bread can be made 2 days ahead. Let cool, then wrap in plastic and chill, or freeze up to 2 months.