Slice the bread. The recipe calls for 2 slices. If you want to scale the recipe up, cut more slices of bread.
Toast the bread on medium. I like my garlic bread lightly browned but you can toast it on whatever settings you prefer to create a softer or crunchier result.
Heat the butter in the microwave on high for 30 seconds. Place a paper towel over the bowl to avoid splattering butter in your microwave.
Now the butter is softened, add the salt and garlic powder to the bowl with the melted butter.
Mash the garlic powder into the melted butter, which creates a garlic butter.
Once the bread is toasted, spread the garlic butter on the 2 slices of bread.
Sprinkle the grated parmesan on top of the garlic butter. If you're freshly grating a block of Parmigiano-Reggiano, grate the cheese until you have a thin coverage over the garlic butter.
If you're using a toaster oven, you can optionally put it back into the toaster oven for 30 seconds to melt the cheese.
Enjoy your 5-minute garlic bread!
Notes
If you don't have a microwave, you can melt the butter by putting the bowl in a pan of warm water.
If you don't have a toaster oven, you can skip melting the cheese. If you really want the cheese to melt and you have a microwave, you can zap it in the microwave for 30 seconds (but there is a small risk of drying out the bread and making it rock hard)
If you prefer to use the broiler in your oven, you can use that instead of a toaster or toaster oven.