In a large bowl, whisk together whole wheat flour, all-purpose flour, ground flaxseed, baking powder, baking soda, and salt until well combined.
To prepare pancakes, combine 1 cup of the dry mix with 1 cup milk, 1 lightly beaten egg, and 2 tablespoons melted coconut oil in a medium bowl. Stir until just combined; the batter may be slightly lumpy.
Heat a non-stick skillet over medium heat and lightly grease it. Pour 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface and the edges look set, about 2-3 minutes. Flip and cook for an additional 1-2 minutes, until golden brown.
Repeat with the remaining batter, adjusting the heat as necessary. Serve warm with your favorite toppings.
Notes
This mix can be stored in an airtight container for up to 3 months. Feel free to add fresh or frozen berries, nuts, or spices like cinnamon to the batter for variety.