Slice French bread lengthwise or use whole naan pieces. Mix softened butter with minced garlic thoroughly. Spread garlic butter evenly but not too thick on bread. Don't drown the bread or it'll get soggy. A thin even layer creates crispy edges.

Shred or chop cooked tandoori chicken into bite-sized pieces. If using plain chicken, toss with tandoori masala, garam masala, and paprika. Add a splash of yogurt if chicken seems dry. Mix in minced garlic and fresh coriander. Taste and adjust spices until noticeably spiced.

Place garlic buttered bread on baking sheet. Spread seasoned chicken evenly across bread surface. Don't pile too much chicken in one spot. Sprinkle shredded mozzarella cheese generously over chicken. Add cheddar for extra flavor if desired.

Preheat oven to 375°F. Bake for 10-12 minutes until cheese melts and bubbles. Switch to broil for last 2-3 minutes for golden brown top. Watch carefully during broiling to prevent burning. Bread edges should be crispy and cheese golden.

Remove from oven when cheese is golden and bubbly. Garnish with fresh chopped cilantro immediately. Add a squeeze of fresh lemon juice over top. Let cool for 2-3 minutes before slicing. Cut into even pieces and serve warm.