Add water and salt to a medium pot. Stir to combine. Add 1 Tbsp butter and bring to a rapid boil over medium-high heat.
Once boiling, add grits and stir for 30 seconds.
Partially cover pot with lid. Reduce heat to medium (or medium-low if stove runs hot). Simmer 15 minutes, stirring every few minutes to prevent sticking.
Remove lid. Add remaining 3 Tbsp butter and stir until melted.
Add heavy cream 2 Tbsp at a time, stirring well after each addition until fully incorporated before adding more.
Continue stirring constantly until grits thicken and begin to sputter, about 15 minutes.
Remove from heat. Taste and add more salt if needed. Serve hot with desired toppings.