In a firepit, build a wood fire about as wide as the cooking grate. Let it burn to low flames and embers (1 to 1 1/2 hours); fire is ready when you can hold your hand 5 in. above grate only 7 to 9 seconds. Or use a charcoal fire that’s about this hot. Clear fire from directly beneath a section of cooking grate to make an area big enough for 6 cones.
Meanwhile, set out ingredients along with a couple of camp cups for holding filled cones upright while you work. Put 3 marshmallows into a cone followed by 2 or 3 strawberry quarters, 2 chunks of chocolate, and 3 more marshmallows. Lay a 12-in. square of heavy-duty foil flat on a work surface and set cone on top, facing a corner. Fold corner over top of cone and opposite corner over tip. Pat down foil around sides of cone and roll to enclose. Repeat to fill remaining cones.
Warm cones on cleared part of cooking grate near fire, using tongs to turn cones over and rotate them often, just until chocolate and marshmallows are softened, 3 to 4 minutes.
Carefully remove hot foil. Tuck about 3 half-slices of strawberries into top of each cone and sprinkle with almonds. Serve cones warm.