Steep fresh thyme sprigs in cream (in fridge) for at least 4 hours, preferably overnight.
Make curd:
Combine lemon juice, zests, and butter in sauce pan over medium low heat until butter is melted. Add remaining ingredients, whisking briskly to incorporate.
Continue heating, stirring regularly, for 10-15 minutes. Do not allow to boil (you don’t want to scramble the eggs).
When mixture is towards the end of this time, stir constantly until thick enough to coat the back of a spoon (makes a very definitive *plop* when falling back into pot).
Strain into a glass container, cover, and chill in fridge.
Prepare tart shells:
Preheat oven to 350F. Place tart pans on a larger baking sheet for ease of movement.
Combine all ingredients in a medium bowl (or the pot you melted the butter in), stirring with a fork until fully incorporated. This will be more like a crumbly paste than a dough.
Using your fingers, press mixture into tart pans until about ¼” thick all around (error on the side of thicker). Prick the bottoms with a fork several times.
Bake for 15-20 minutes (depending on size of the tarts) until just starting to turn golden. Remove and allow to cool in the pans.
Make the cream:
Strain the thyme from the cream using a fine mesh sieve or cheese cloth. Press to express all the flavor from the thyme.
Whip cream to soft peaks by whatever your preferred methodology – as previously mentioned, I like to do so manually.
Add honey and granulated sugar, continue beating until cream is stiff (but not butter).
Fold in lemon curd using gentle, repetitive, round motions until completely combined. Chill until shells are cool and ready.
Unmold shells, pressing up from the removable base and very gently handle by the sides while removing said base.
Place shells on a tray or flat plate that can fit in the fridge. Fill to just level (maybe a little over for smaller tarts) with the top edge of the crust.
Drizzle/pipe/dollop a small amount of lemon curd (1-2 tsp) on the tops in a decorative manner – I like the non-uniform look.
Place the fridge for 1-2 hours (depending on size) before attempting to cut or photograph. Garnish with a sprinkle of thyme leaves just before serving.