With a vegetable peeler, peel the lemon zest off in long strips and juice the lemons. Peel and slice the shallots into rings. Add the butter, lemon zest strips, lemon juice, thyme, shallot slices, one tablespoon of the Aleppo pepper and and a pinch of salt to a heavy bottom saucepan.
Place over medium low heat and melt slowly. Turn to low and let butter infuse with the aromatics for 20 minutes. Add the shrimp and let them slowly poach in the warm butter until just opaque in the center, about 5 minutes. Remove the shrimp from the butter and serve over crostini, with a drizzle of the butter, the remaining Aleppo pepper and Maldon sea salt.