In a bowl, combine rye flour, wheat flour, baking powder, and salt. Stir to combine. In a separate bowl, whisk together eggs, walnut oil, sorghum, yogurt, milk, and vanilla extract. Pour into dry ingredients and stir until combined.
Pour a 1/4 of the batter into a waffle iron and cook according to iron's instructions (usually 3-4 minutes for my iron). Remove from iron and place on a baking tray. place tray in oven and keep waffles warm while making the rest.
While waffles cook, combine black raspberries, maple syrup, and lemon juice in a small sauce pan. Bring to a boil and reduce to a simmer. Continue to simmer until ready to use.
In a bowl, enthusiastically whisk heavy cream until it becomes whipped cream. Whisk in maple syrup.
Serve waffles with a few spoonfuls of black raspberries and a dollop of whipped cream.