Wash and dry Spinach leaves. Lightly toast slivered almonds in a heavy skillet over medium heat until fragrance is released. Rough cut Garlic cloves. Put the Spinach leaves, olive oil, Parmesan cheese, almonds, Garlic, lemon zest and lemon juice in the bowl of a food processor. Pureé, scraping down sides to incorporate all ingredients. Freeze in airtight freezer bags for up to six months.