Prep the pan: Heat the oven to 350°F (175°C). Line an 8x8-inch pan with parchment, letting it overhang for easy lifting. Lightly grease the sides.

Toast the dry mix: On a sheet pan, spread the oats, nuts, seeds, and coconut. Toast for 8–10 minutes, stirring once, until lightly golden and fragrant. Let cool slightly.

Whisk the wet ingredients: In a large bowl, whisk the sourdough discard, honey or maple, brown sugar (if using), nut butter, oil, egg, and vanilla until smooth and glossy.

Add the seasonings: Whisk in the salt, cinnamon, and baking soda. This keeps the flavor balanced and helps the bars set.

Combine: Add the toasted oat mixture to the bowl and stir until every oat is coated. Fold in the dried fruit and chocolate (if using). The mixture should be thick and sticky.

Press firmly: Scrape the mixture into the prepared pan. Use a spatula or the bottom of a measuring cup to press it down very firmly, especially into the corners. A tight pack equals tidy slices.

Bake: Bake for 20–25 minutes, until the top is set and lightly browned at the edges. For crisper bars, go up to 28 minutes; for chewier, pull them earlier.

Cool completely: Place the pan on a rack and cool fully, at least 1 hour. Don’t rush this step—cooling helps the bars firm up.

Slice: Lift out using the parchment and cut into 12–16 bars with a sharp knife. Wipe the blade between cuts for clean edges.