Put 2 tablespoons whole chia seeds into the completely dry Ninja BN801 pitcher. Seat the pitcher securely on the base.
Pulse until the seeds become a coarse, evenly speckled flour with no layer of whole seeds at the bottom. Stop before the flour warms or smears toward seed butter.
Measure 2 tablespoons coarse chia flour into a small glass or ceramic ramekin. Add 1 teaspoon homemade 24-hour sour cream and stir until no dry flour remains and the mixture holds firm ridges.
Scrape down the ramekin, cover loosely with a small glass plate, and leave at 68 to 72°F for a full 24 hours.
After 24 hours, use the entire cohesive, gently tangy batch in the linked pizza bake. If the casserole is not being assembled immediately, cover and refrigerate the small batch until needed.