In a small bowl, whisk together the flour, sugar, baking powder, and salt.
Mix in crushed pretzels.
In a separate, medium-sized bowl, whisk together stout, melted butter, egg, and vanilla (if you want less of a stout flavor, use ½ buttermilk and ½ stout here).
Pour the dry ingredients into the wet ingredients, stirring until they’re just combined, but taking care not to over mix.
Heat a griddle or frying pan over medium heat and pour about ¼ cup batter onto it. Cook pancakes for about 1-2 minutes on each side, until they’re nicely browned and cooked through. Repeat with all batter.
Serve stacks of pancakes with toffee sauce poured over them. Sprinkle additional crushed pretzels and toffee pieces on top if desired.