Bake-ahead sheet or one-layer cakes and fairly sturdy bar cookies are ideal for preparing in advance and transporting to an event. Bar cookies can be cut into squares or rectangles, and gently layered between sheets of waxed paper or cooking parchment paper within sturdy containers. Sweets baked in rectangular, square, or round pans (each single, not multiple-layer) are easy travellers, whether frosted or not–leave the dessert in the pan, cover, and place the baking pan in a larger pan for safe delivery.
From Baking by Flavor, the following items are ideal for contributing to a potluck dinner: Kitchen Sink Buttercrunch Bars (page 209), Caramel, Nougat, and Walnut Candy Bar Cake (page 235, and following page), Sour Cream Fudge Cake (page 260, and following pages), Simply Intense Chocolate Brownies (page 280, and following page), or Cream Cheese-Swirled Brownies (page 492, and following page). From ChocolateChocolate: Bittersweet Chocolate Brownies (page 76), Supremely Fudgy Brownies (page 81), White Chocolate Chip and Chunk Blondies (page 145), Layered Toffee Bars (page 176), or Buttery and Soft Chocolate Cake for a Crowd (page 403, and following page). From Baking Style: Art, Craft, Recipes, A Noble Marzipan Cake (page 41, and following page), A Gentle Banana Cake (page 118), Date Bars, Big and Crazy Chewy (page 163), Confection Brownies (page 178), Moist and Chewy Fruit Slice (page 322, and following page), Blondie Cake (page 409), or A Decadent Streusel Coffee Cake (page 467).