2 cups old-fashioned rolled oats (certified gluten-free)
3/4 cup shelled pistachios
3/4 cup chopped dried apricots
3/4 cup unsweetened shredded coconut
1/2 cup sunflower seeds
1/2 cup pepitas
1/2 cup whole flax seeds
1/3 cup psyllium husks
3 tablespoons chia seeds
2 teaspoons kosher salt or sea salt
1 teaspoon vanilla extract
1 teaspoon cinnamon
1/8 teaspoon cardamom
2 1/2 cups water
1/4 cup maple syrup
1/4 cup extra-virgin olive oil
→ Optional: Before mixing the dough, toast the pistachios, sunflower seeds, and pepitas (toast them in the oven for about 10 minutes at 350°F, until very fragrant). It's not strictly necessary, but gives the bread another layer of toasty flavor.
Combine all the dry ingredients and the spices in a bowl. Pour over the water, maple syrup, and olive oil. Use a stiff spatula to stir everything into a wet, sticky mash — keep mixing until all the water has been absorbed and no longer pools on the bottom of the bowl.
Oil a loaf pan (8 1/2 x 4 1/2-inches). Scrape the mixture into the pan, press it firmly in, and smooth the top. It will fill the entire pan and be slightly mounded on top. Poke any visible apricots below the surface if burnt bits bother you (they toast more quickly than the rest of the ingredients in the oven). Cover and refrigerate the loaf for at least 2 hours or up to 24 hours.
About an hour before you want to bake, remove the loaf from the fridge and let it sit on the counter to take the chill off. Preheat the oven to 400°F with a rack in the middle position.
Bake the loaf for 1 1/2 hours — check the bread every 10 minutes in the last half hour and tent with foil when the top is deep golden and looks to be on the verge of (but not yet!) burning. When done, the bread will be dark golden brown on top, pull away from the sides of the pan, and register 190°F in the middle with an instant-read thermometer. This is a dense loaf — it takes a while to bake all the way through. I've found that checking the internal temperature is the best way to know that it's done.
When done, transfer the bread from the pan to a cooling rack and cool for at least 2 hours, until no longer warm at all. If you cut the loaf before it's fully cooled, you may find that it's gummy in the middle.
To serve, slice thinly and toast until crispy and fragrant. Spread with butter or jam, or eat it just as it is!