Preheat grill to high.

Blend tamarind concentrate, dates, agave syrup, ginger, cumin, 1/4 teaspoon salt and cayenne (if using) in a blender until smooth.

Cut each block of tofu crosswise into eight 1/2-inch-thick slices. Lightly brush each slice with oil and season on both sides with a light sprinkle of curry powder, the remaining 1/4 teaspoon salt and pepper.

Oil the grill rack (see Tip). Grill the tofu slices until golden and heated through, 2 to 3 minutes on each side. Serve hot with the tamarind chutney for dipping.

Notes: Tamarind is a tropical tree that produces a sour-sweet fruit in a brown pod, with edible pulp. It's used in Asian and Indian curries, beverages and desserts. Purchase either tamarind concentrate or pulp. We found Thai brands of concentrate and pulp to work best in this recipe; Indian brands were too thick, dense and strong in flavor. To make your own concentrate combine 1/4 cup tamarind pulp and 1 cup hot water in a medium bowl. Let stand for 20 minutes. Break up the paste and mix it with the water with a fork. Pass the mixture through a fine sieve set over a bowl, pressing against the sieve to collect as much of the pulp as possible. Discard solids.

Agave syrup or nectar is the naturally sweet juice extracted from the agave plant. It has a lower glycemic index and is lower in calories than table sugar, but is even sweeter. Use it in moderation when substituting for table sugar. Look for it near other sweeteners in health food stores.

Tip: How to oil a grill rack: Oil a folded paper towel, hold it with tongs and rub it over the rack. (Do not use cooking spray on a hot grill.)

MAKE AHEAD TIP: Cover and refrigerate the chutney (Step 2) for up to 1 week.