Quarter head of cauliflower; cut quarters in 1/2 inch thick slices. Small florets may crumble off; keep with slices.
Place cauliflower on parchment paper lined baking sheet. Drizzle oil over cauliflower, coating all surfaces. Sprinkle and toss with salt; Top cauliflower with few cranks of black pepper. Sprinkle cumin and fennel seeds evenly overall. Cover sheet with aluminum foil. Bake 20 minutes. Remove foil and sprinkle cauliflower with curry powder. Bake, uncovered, 10-15 minutes or until cauliflower is tender, but not too soft. Remove from oven to cool.
Reset oven to broil.
Spread butter on 1 side of all bread slices. Turn half the slices over so unbuttered side is up. Spread chutney or marmalade over these slices, using about half the chutney. Place 2 slices Kaltbach Le Gruyère over each of the 4 bread slices. Top cheese with cauliflower, dividing evenly.
Turn remaining buttered bread slices over so plain side is up. Spread remaining chutney over these slices. Place them over stacked cauliflower slices so buttered side is up. Close sandwiches; arrange in large sauté pan over medium-low heat. Weight sandwiches with lid or another pan (or use a panini press). Grill sandwiches 2-3 minutes; flip and grill other side about a minute.
Turn sandwiches over again and divide remaining Kaltbach Le Gruyère slices (2 per sandwich) directly on top of each sandwich. Set under heated broiler a few seconds until cheese begins to melt, caring not to burn the bread. Halve sandwiches and serve immediately.
Note: To make a quick version of chutney- mix 1/4 cup apricot or orange marmelade with 1 teaspoon fresh grated ginger, 1 teaspoon fresh grated turmeric or 1/2 teaspoon powdered turmeric, 1-2 teaspoons white wine vinegar and/or lime juice, pinch salt and few cranks of ground pepper, and 1/4 teaspoon cayenne pepper.