In a large bowl combine oil, butter, eggs and honey. Mix by hand or with a mixer on low speed until just combined.
In a separate medium-sized bowl sift together white rice flour, tapioca starch, xanthan gum, baking soda, and salt.
Alternatively add dry ingredients to the butter/honey bowl with the lemon juice and milk until all are added. Mix by hand or with a mixer on low speed.
Dab the thawed blueberries with a paper towel to remove excess moisture. Hand mix in the blueberries and lemon zest until just combined. *
Line 12 muffin cups with muffin papers and spray with a bit of non-stick cooking spray. Divide muffin batter into equal amounts between the cups.
Bake for 23-26 minutes**, or until a toothpick can be inserted in and comes out clean.
Notes
*Try not to overmix so the blueberries do not bleed their color into the rest of the muffin batter. **If using fresh blueberries: Your cook time may be less. Make sure to watch the muffins at around 22 minutes to see if they are done!