This is such a nice fresh appetizer and so easy to make. Don't shy away because there are 3-4 steps; it is actually very very easy, and so worth making. The ricotta will last 5 days (approx) in the refrigerator, and very important is to make sure to use good fresh milk and cream. I like to top my crostini with the arugula then the ricotta and tomato, but feel free to skip the arugula. To me it is such a nice compliment to the creamy ricotta. These bite size appetizers and a bowl of soup or a salad can be dinner for me.