How to Make It
In a food processor, combine the cheddar with the beer, garlic, mustard and cayenne and blend until smooth. Season the beer cheese with salt.
Preheat the broiler. Spread the toasts with the beer cheese and arrange them on a rimmed baking sheet. Broil the toasts 6 inches from the heat for about 2 minutes, rotating the pan, until the cheese is bubbling and browned around the edges. Top with tomato slices and serve.