Let cheeses stand at room temperature for 30 minutes. In a large food processor or mixing bowl combine cream cheese, gruyere cheese, and blue cheese. Process or beat until well combined.
Line one 7-1/2x3-1/2x2-inch loaf pan or a 3-quart bowl with plastic wrap.
For Skillet Roasted Tomato Topper, spread half the cheese mixture in pan or bowl; spoon half the topper over cheese. Cover and refrigerate remaining topper. Carefully spoon on remaining cheese mixture and spread evenly. Cover and chill for 2 to 24 hours.
For Apple-Jalapeno Topper, spread cheese mixture in loaf pan or bowl; cover and chill 2 to 24 hours.
To serve, unmold cheese onto a serving platter, removing plastic wrap. Top with remaining topper. (If making Apple-Onion Topper, sprinkle with 1/4 cup pistachio nuts, if desired.) Serve cheese appetizers with crackers, flatbreads, fresh vegetables, or fruits. Makes 24 (2-tablespoon) servings.
Apple Jalapeno Topper
Combine apple, green onions, lemon juice, jalapeno pepper and sugar.
Skillet Roasted Tomato Topper
In a skillet heat olive oil over medium-high heat. Add red onion. Cook, stirring occasionally, until lightly browned. Add cherry tomatoes, vinegar, garlic, and tarragon. Simmer, uncovered, until most of the liquid is evaporated. Remove from heat; cool slightly.