Prep your pan. Line a 9x13-inch pan with parchment so it overhangs on two sides. This makes lifting the slab out much easier later.

Mix the dry cookie ingredients. In a bowl, whisk oat flour, protein powder, coconut sugar, baking powder, and a pinch of salt. Aim for a smooth, even mix.

Add the wet ingredients. Stir in applesauce, egg white, almond milk, and vanilla. The batter should be thick but spreadable. If it’s too stiff, add a tablespoon of milk at a time. Fold in mini chocolate chips if using.

Bake the first cookie layer. Spread half the batter evenly in the lined pan. Bake at 350°F (175°C) for 8–10 minutes, just until set and lightly puffed. You want soft, not crisp.

Cool briefly. Lift the layer out with the parchment and set aside to cool. Re-line the pan with fresh parchment.

Bake the second cookie layer. Spread the remaining batter into the pan and bake the same way. Let both layers cool completely. Soft layers are key to biteable sandwiches after freezing.

Make the cheesecake filling. In a mixing bowl, beat softened light cream cheese until smooth. Add Greek yogurt, protein powder, powdered sweetener, vanilla, and a pinch of salt. Beat until fluffy and glossy. Taste and adjust sweetness. A little lemon zest adds cheesecake tang.

Assemble the slab. Place one cooled cookie layer back into the lined pan. Spread the cheesecake filling evenly across. Top with the second layer, pressing gently so it adheres without squeezing out the filling.

Freeze until firm. Cover and freeze for 3–4 hours, or until the filling is solid enough to slice cleanly.

Slice into sandwiches. Lift the whole slab out using the parchment. Use a sharp knife to cut into rectangles. Wipe the blade between cuts for neat edges.

Wrap and store. Wrap each sandwich in parchment or plastic wrap and place in a freezer-safe bag or container. Label with the date.

Serve. Let a sandwich sit at room temp for 3–5 minutes before eating for the perfect soft-serve bite.