Prep the pan. Line an 8x8-inch square pan with parchment, leaving flaps on two sides for easy lifting. Lightly grease the parchment if your nut butter is very sticky.

Warm the binder. In a small saucepan over low heat, gently warm the nut butter and honey or maple syrup, stirring until smooth and pourable. Don’t boil. Stir in the vanilla and salt.

Mix with oats. Add rolled oats to a large bowl. Pour the warm mixture over the oats. Stir until every oat looks glossy and coated. If using chocolate chips, let the mixture cool for 2–3 minutes first to prevent melting.

Fold in add-ins (optional). Mix in any extras. Keep the total add-ins to about 1/2 cup so the bars stay cohesive.

Pack it tight. Transfer the mixture to the lined pan. Press down firmly with the back of a measuring cup or a piece of parchment. The tighter you pack, the cleaner the slices.

Choose your set method. No-bake: Chill in the fridge for 1–2 hours, or until firm.

Lightly baked: Bake at 325°F (165°C) for 12–15 minutes, just until the edges look set and lightly golden. Cool completely in the pan.

Slice and store. Lift out using the parchment flaps. Cut into bars or squares with a sharp knife. Wipe the blade between cuts for neat edges.