In a large bowl, whisk together flour, ground flaxseeds, salt & baking powder. Stir in eggs, canola oil & milk. Mix until well-combined.
In a small bowl, mix together pumpkin puree, brown sugar & cinnamon. Fill a quart-sized plastic bag with mixture & set aside.
In separate bowl, mix together Greek yogurt, brown sugar, cinnamon & vanilla extract. Set aside.
Heat griddle to medium heat. Once heated, lightly grease surface with olive oil. Scoop ¼ cup batter per pancake onto griddle.
Cut a small hole in the corner of the pumpkin filling. Once batter is bubbly, swirl pumpkin filling in a circular motion onto each pancake. (Be careful not to get too close to the edge). Flip pancakes and cook an additional 2-3 minutes. Remove pancakes from griddle, drizzle with Greek yogurt topping & sprinkle with chopped walnuts. Enjoy with your favorite Canadian bacon or eggs for a balanced breakfast!