Slowly drizzle in the oils, whisking constantly until the aïoli is thick. Stir in the lemon juice and horseradish, and season to taste with salt and pepper. To Assemble Sandwiches Grill each ...

3 Tablespoons harissa paste, ½ teaspoon salt, 1 ½ Tablespoons lemon juice Taste and adjust seasoning as needed, adding more ...