In a small saucepan, combine honey, red pepper flakes, and optional apple cider vinegar. Gently heat over low for 5-7 minutes until fluid; do not boil. Let steep for 15-20 minutes.

Strain if desired and store at room temperature.

Cook beef bacon until crispy, either stovetop or oven.

Stovetop: Preheat skillet over medium heat, and cook 8-12 minutes, flipping.

Oven: Bake at 400°F (200°C) for 15-20 minutes on a lined baking sheet.

Drain on paper towels, reserving about 1 tablespoon rendered fat, and break bacon into 2-3 pieces.

Wash, core, and thinly slice the Granny Smith apple.

Grate or thinly slice the sharp cheddar cheese.

Butter one side of all bread slices. On 4 unbuttered sides, layer half the cheddar cheese, then apple slices, followed by broken beef bacon.

Drizzle 1 tablespoon hot honey over each and top with remaining cheddar cheese.

Place the remaining bread slices on top, butter-side-up.

Preheat a skillet over medium-low heat with reserved bacon fat or butter.

Place sandwiches butter-side down, and cook for 4-6 minutes per side until golden-brown and cheese is melted.

Let the grilled sandwiches rest for 2-3 minutes before cutting diagonally.

Sprinkle with flaky sea salt or extra hot honey, and serve immediately.