Directions

1. Attach multipurpose blade to KitchenAid® 7-Cup Food Processor. Add flour and butter to work bowl. Pulse until mixture resembles coarse breadcrumbs. Add cold water and process until dough forms a ball. Gather dough together and form a flattened disc. Wrap in plastic wrap and chill for 45 minutes.
2. Attach clean work bowl and shredding disc to food processor. Shred Gruyère cheese on low speed and set aside. Turn shredding disc over to slicing disc. Cut tomatoes to fit feed tube and process on low speed to slice.
3. Preheat oven to 350°F. Roll pastry out on a lightly floured surface to form a 16 x 8-inch rectangle. Ease dough into a 14 x 6-inch rectangular tart pan. Trim edges and brush dough liberally with mustard. Sprinkle with Gruyère cheese and arrange sliced ​​tomatoes on top of cheese. Season with salt and pepper and drizzle with olive oil. Bake in preheated oven for 35 minutes or until golden brown. Cool slightly before serving.