Preheat oven to 325 degrees. In a small saucepan, bring the cream, milk, and tea leaves just to a boil over medium heat. Turn off heat; let steep at least 30 minutes but no more than 2 hours.
In a medium bowl, whisk together egg yolks, sugar, lemon zest, and salt. Reheat infused cream over medium heat; slowly whisk into yolk mixture. Strain through a fine sieve into a bowl to extract as much liquid as possible without pressing on tea leaves. Discard leaves.
Working close to the oven to minimize risk of spilling water, arrange four 6-ounce ovenproof cups in a baking pan large enough to hold the cups without touching one another. Pour boiling water into pan, being careful not to splash any inside cups, until water comes halfway up sides of the cups.
Divide infused liquid among cups. Cover pan tightly with aluminum foil, poking a few holes to let steam escape. Bake until custards are set but still slightly wobbly in centers, about 30 minutes.
Carefully remove baking pan from oven; remove foil. Transfer cups from the hot water to a wire rack; let cool about 30 minutes. Cover cups with plastic wrap; chill in the refrigerator until custards are firm, at least 2 hours and up to 3 days. Serve with Honey Lace Cookies on the side.