Measure the milk in a glass measuring cup, then warm it in the microwave until it reaches 105-115°F.
Add the sugar and yeast to the warmed milk, then let the mixture sit for about 10 minutes.
In a large bowl, whisk together the all-purpose flour, whole wheat flour, and flax meal.
Add 3 cups of the flour mixture, the egg, and the milk mixture to the bowl of a stand mixer. Use the paddle attachment to mix until smooth, then cover and let stand for 15 minutes.
Remove the paddle attachment and connect the dough hook. Add ¾ of a cup more of the flour mixture plus the salt, then mix until smooth.
1 tablespoon at a time, add the remaining flour mixture and continue to mix until the dough clings to the hook and pulls away from the sides of the bowl.
Turn the dough out onto a lightly floured surface. Knead the dough with your hands for about 5 minutes or until it’s smooth and elastic.
Coat the inside of a glass bowl with cooking spray. Place the dough in the bowl, then move it around and turn it over until all sides are coated with the oil.
Cover the bowl with a towel and allow the dough to rise until it has doubled in size, about an hour.
When you think the dough is ready, press two fingers into it. If indentations remain, the dough has risen enough. Punch the dough down, cover, and let it rest for another 5 minutes.
Dust a baking sheet with cornmeal and divide the dough into 16 equal portions in the bowl.
Grab one portion at a time, leaving the remaining dough covered. Roll each portion into an 8-inch rope, tie it into a knot, tuck the ends under, and place it on the baking sheet. Repeat until you’ve used all of the dough.
Cover the knots with a towel and let them rise until they’ve doubled in size, about 30 minutes.
Preheat the oven to 400°F. Gently brush the rolls with butter, then sprinkle with flaxseeds.
Place in the oven and bake for 20 minutes or until the rolls are lightly browned on top and hollow-sounding when you thump them.