Prepare the bechamel sauce by mixing olive oil and flour. Heat milk in a saucepan, add the olive oil-flour mixture, and stir until smooth. Bring to a boil.

Remove the shrimp's vein and slice them in half lengthwise.

Cut cabbage and broccoli into bite-sized pieces. Mix them in a bowl with salt and breadcrumbs.

Transfer the vegetables to a microwave-safe dish. Add bechamel sauce and shrimp on top. Sprinkle with salt, mayonnaise, and grated cheese. Cover with plastic wrap and microwave for 7–8 minutes.