Preheat oven to 350°.
Place the milk into a microwave-safe mug. Heat on high for 30-40 seconds until steaming hot. Place an earl grey tea bag in the hot milk and let it steep for 2 minutes.
Line an 8" by 4" loaf pan with parchment paper. Set aside.
Separate egg whites from the egg yolks and place the egg whites into an clean stand mixer bowl with a whisk attachment. Be sure that the mixer bowl is free from any grease.
Place the egg yolks into a large glass bowl. Add oil, sugar, bergamot oil, and orange zest. Use a whisk and beat together until combined.
Gradually add the steeped tea (in milk) to the egg yolks, while whisking constantly as to not scramble the eggs.
Add the flour mixture to the egg yolks and mix until combined.
Beat the egg whites using the stand mixer whisk attachment on low speed. Once bubbles form, add the cream of tartar and gradually increase the speed. When you can see trails forming, gradually add the sugar and beat until stiff peaks form.
Gently fold the egg whites into the flour mixture. Use about ½ C at first to loosen up the mixture. Then fold in the rest of the egg whites, until no white streaks remain.
Place the batter into the prepared loaf pan.
Drop the pan a few times to release any trapped air bubbles.
Bake at 350°F for 55-60 minutes, or until a toothpick inserted comes out clean.
Cool in the pan for 10-15 minutes before transferring to a wire rack to completely cool.
Serve with tea and store at room temperature for up to 3 days, covered.