In a pot over medium high heat, melt the butter. Add the garlic and cook until fragrant, about 30 seconds.
Add the beer, cream and lemon juice; reduce heat to maintain a simmer. About a tablespoon at a time, add the Parmesan, stirring until melted before adding more.
Add the dry pasta, water and peas, simmer, stirring frequently, until pasta is al dente and the sauce has thickened, about 10 minutes. Serve immediately.
Notes
To make this recipe using fresh, not dried, pasta, omit the water.