In a large mixing bowl or the bowl of a stand mixer (if using one), whisk together the flours, the multigrain blend, the salt, and the yeast.*
Melt the butter in a small or medium saucepan. Stir in the maple syrup and water. Allow the water to come to about 110F (hot to the touch, but not painful—you can use a probe thermometer or touch).
Add the liquid to the dry ingredients. Use a spatula to mix everything into a sticky dough ball. Turn the dough out onto a floured surface and knead for 10 minutes, or until the dough is becoming smooth and supple. Alternately, you can mix wet and dry ingredients in the bowl of your stand mixer, fitted with the dough hook. Knead on medium low speed (3 or 4) for 5 minutes.
Transfer the dough to an oiled bowl. Allow it to rise for 1 hour, or until doubled in size.
Use vegan butter to grease a standard loaf pan (8. 5 x 4. 5 x 2. 75 inch). Lightly oil a work surface. Transfer the dough to the work surface. Shape it into a rectangle that’s about 9” x 13”, with a short end facing you. Starting at the top edge, roll the dough into a log about 4” x 8”. Gently tuck the ends in and make sure the seam of the bread is underneath the roll. Gently transfer the roll to your prepared loaf pan.
Allow your bread to rise, uncovered, for another 30-60 minutes, until it has risen about 1 ½” inches above the edge of your loaf pan. About 15 minutes after the bread begins this second rise, preheat your oven to 350 degrees F.
Bake the bread for 30-40 minutes, or until it's a deep golden brown on top. A probe thermometer should register at least 190F in the center of the bread, and/or the bottom should sound hollow when tapped. Remove the bread from the loaf pan and transfer it to a cooling rack. Allow the bread to cool completely before slicing and storing.