1. Combine first 5 ingredients in a small bowl, stirring to combine. Set aside.
2. Dissolve honey and yeast in 1 1/2 cups warm water in a medium bowl; let stand 5 minutes.
3. Weigh or lightly spoon flour, potato starch, and cornstarch into dry measuring cups; level with a knife. Place flour, potato starch, cornstarch, xanthan gum, baking powder, and salt in a large bowl; beat with a mixer at medium speed until blended. Add seed mixture, yeast mixture, oil, vinegar, and eggs; beat at low speed until blended.
4. Spoon batter into a 9 x 5-inch loaf pan coated with cooking spray. Cover with plastic wrap coated with cooking spray, and let rise in a warm place (85°), free from drafts, 45 minutes or until dough reaches top of pan.
5. Preheat oven to 375°.
6. Bake at 375° for 45 minutes or until loaf sounds hollow when tapped. Cool 10 minutes in pan on a wire rack; remove from pan. Cool completely on wire rack.