Preheat your waffle iron.
In a medium bowl, whisk together the flour, sugar, baking powder, baking soda and salt.
In a large bowl, whisk together buttermilk, butter and eggs; add flour mixture and mix until just combined.
Divide the batter evenly between three bowls. In one bowl, stir in the vanilla extract. In another bowl, stir in the melted chocolate until thoroughly combined. In the third bowl, stir in the strawberry powder and red food color if using.
Coat the waffle iron with cooking spray. Take a heaping spoonful of the strawberry batter and pour it into a stripe in the waffle iron; use the back of the spoon to spread it into place if needed. Spoon a stripe of the vanilla batter next to the strawberry batter, spreading it into place. Put a stripe of chocolate batter next to the waffle batter. All three lines of batter should be touching each other.
Close the waffle iron and cook according to manufacturer instructions (my waffles cook for 4-5 minutes). Repeat the cooking process with the remaining batter.
Serve the waffles with a drizzle of chocolate sauce, a dollop of vanilla yogurt and fresh strawberries.