Line an 8x8-inch pan with parchment, leaving overhang for easy lifting. Lightly grease the sides.

In a large bowl, add the crispy rice cereal. Keep it nearby—you’ll need it quickly once the mixture is warm.

In a small saucepan over low heat, melt the butter (or coconut oil), Biscoff spread, and honey. Stir until smooth and just warm, about 2–3 minutes. Do not boil.

Remove from heat and whisk in the vanilla, salt, and protein powder until fully combined. If the mix looks too thick, add 1–2 teaspoons warm water to loosen.

Pour the warm mixture over the cereal. Using a spatula, fold gently until every piece is coated. Work quickly to keep things pliable.

Transfer to the prepared pan. Press the mixture firmly and evenly with a spatula or lightly greased hands. Compact well so the bars hold together.

Melt the chocolate chips with the oil in the microwave in 20–30 second bursts, stirring until smooth. Drizzle or spread over the top. Sprinkle crushed Biscoff cookies if using.

Chill for 30–45 minutes, or until set. Lift out with the parchment and slice into 12 squares with a sharp knife.