For the Bacon and Tomato Jam: Heat tomatoes, bacon, salt, pepper, garlic, vinegar, and sugar over medium-high heat until they bubble up. Reduce heat and cook jam over medium-low heat about 30 minutes until thick.
For the sammies: Butter one side of sliced bread and build sandwiches with buttered sides facing out. Spread sandwiches with jam on one side and stack up bacon, tomatoes, chives or shallots, cheese and set top into place. Heat a skillet over medium heat and cover with foil. Cook to deep golden, 7-8 minutes, turning occasionally and pressing sandwich as it cooks.