In a large bowl, whisk together whole wheat flour, 1/2 cup of all-purpose flour, salt, yeast, and thyme.
Heat buttermilk until just warmed; it should feel comfortable to the touch on your inner wrist. Whisk in butter and honey, then whisk mixture into the dry ingredients until incorporated. Gradually add remaining flour until a cohesive dough is formed.
Turn dough onto a lightly floured board and knead, adding flour as needed, until dough is smooth and only slightly tacky to the touch.
Place dough in a greased bowl, cover, and let rise until doubled. Grease a muffin tin.
Deflate dough and divide into 24 equal pieces. Roll each piece into a ball, then place two balls into each cup of the muffin tin. Cover and let rise until puffy and just about doubled.
Preheat oven to 375°F and bake rolls for 20 minutes, until golden brown.