Preheat the Oven: Start by setting your oven to 350°F.
Infuse the Milk: Pour the milk into a small saucepan and gently warm it over low heat. Steep the Earl Grey tea bag in the warm milk for 10-15 minutes to infuse it with flavor. Remove the tea bag after infusion.
Cream Butter and Sugars: In a large mixing bowl, using a stand mixer or an electric whisk, beat the butter, white sugar, and light brown sugar together until the mixture becomes soft and fluffy.
Add Bananas, Milk, and Lemon Juice: To the creamed butter and sugars, add the mashed bananas along with the Earl Grey-infused milk and lemon juice. Mix until these are well combined. The mixture may appear to be split at this point, but don't worry; this is normal.
Incorporate Eggs: Beat in the eggs one at a time, ensuring each egg is fully integrated into the mixture before adding the next.
Combine Dry Ingredients: In a separate bowl, whisk together the all-purpose flour and cinnamon. Gradually add this to the wet mixture, mixing until just combined to avoid overworking the flour.
Fold in Chocolate: Gently fold the chopped chocolate into the batter, ensuring it's evenly distributed.
Prepare Muffin Tins: Grease a 12-cup muffin tin or line it with muffin papers. Fill each cup about ¾ full with the muffin batter. Lightly sprinkle the top of each muffin with a pinch of sea salt for an extra flavor contrast.
Bake: Place the muffin tin in the preheated oven and bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Cooling: Allow the muffins to cool in the pan for a few minutes before transferring them to a wire rack to cool completely.