In a medium saucepan, melt the butter over medium heat.
Add the sugar, milk, and salt. Stir and bring to a boil.
Boil the mixture for 1 minute, stirring frequently.
Remove from heat and stir in lemon zest and lemon juice.
Mix in the oats until fully combined.
Drop spoonfuls onto wax paper and let cool for at least 30 minutes before serving.