Place the cereal mix in bowl of stand mixer fitted with dough hook and pour boiling water over it then let stand, stirring occasionally, until mixture cools to about 37 degrees and resembles thick porridge. This can take up to an hour. Sift the flours together in separate bowl.
Once grain mixture has cooled, add honey, butter, and yeast then mix on low speed until combined. Add flour mixture a 1/2 cup at a time then knead until a cohesive ball starts to form. Place in a bowl and cover tightly with plastic wrap and let dough rest for 20 minutes.
Add salt and knead on medium-low speed until dough clears sides of bowl, 3-4 minutes then and additional 5 minutes. Transfer the dough to lightly floured counter and knead by hand until seeds are dispersed evenly and dough forms a smooth round ball. Place dough in large, lightly greased bowl. Cover tightly with plastic and let rise at room temperature until nearly doubled in size; 45-60 minutes.
Grease two 22 x 12cm loaf tins. Transfer dough to lightly floured counter and divide in half. Gently kneed each and form into a rolls. Place one roll in each prepared tin. Spray loaves lightly with water or vegetable oil then sprinkle with sesame seeds. Cover each loaf loosely with greased plastic wrap and let rise at room temperature until nearly doubled in size; about 30-40 minutes. Dough should barely spring back when poked with knuckle.
Thirty minutes before baking, adjust oven rack to middle position and heat oven to 190 degrees C.
Bake until loaves for 35 to 40 minutes then transfer the tins to a wire rack and let cool for 5 minutes. Remove loaves from tins the return to the rack and cool to room temperature before eating.