In a 2 cup measuring cup, make a buttermilk mixture (mix milk and 1 tbsp. white vinegar or lemon juice), set aside.
In a medium mixing bowl, whisk the flour, sugar, baking powder, baking soda and salt. Set aside.
Add the sourdough discard to the measuring cup of buttermilk and mix well to combine.
Pour the buttermilk-sourdough mixture into the dry ingredients, and finally add in the avocado oil. Whisk just until ingredients are mixed and all come together into a batter. Try not to overmix. You will begin to notice the batter getting a bit bubbly as it sits on the counter while heating the pan.
Cook over medium heat either on a skillet or griddle. Flip halfway through cooking time until both sides are golden brown and cooked through.
Serve immediately or place on a wire rack to cool. Freeze completely cooled pancakes in a zip-top bag for up to 2 months.