Step #1 Bring salted water to a boil in large pot.
Step #2 Wash & inspect beans.
Step #3 Heat olive oil in a heavy 10 inch frying pan.
Step #4 (I use cast iron.
Step #5 ).
Step #6 Carefully immerse beans in water for no more than 2 mins.
Step #7 Do not dump out water; scoop out beans with tongs or strainer into colander.
Step #8 Run cold water over beans in sink to stop cooking & set aside.
Step #9 Return water to boil & cook tortellini according to instructions of package OR if you are making fresh tortellini from a recipe, save this step till after beans & sauce are done so that they will be hot & not over cooked.
Step #10 While waiting for tortellini to cook add onion & garlic to olive oil, brown slightly & add beans.
Step #11 Stir frequently; if they need more oil add some of the butter now.
Step #12 When beans begin to sizzle remove them, leaving most of the onions & garlic behind, with tongs to covered bowl & keep warm.
Step #13 Be sure to keep an eye on the tortellini & stir them.
Step #14 Add the rest of the butter to pan & stir.
Step #15 Stir in half of the milk lower the heat to medium.
Step #16 Mix the rest of the milk with corn starch in a c or jar & set aside for a moment.
Step #17 Stir half of the cheese, & all of the pepper, & Mrs.
Step #18 Dash into pan with a whisk.
Step #19 Stir in the rest of the milk mixture & stir until thickened.
Step #20 Set heat to low & slowly stir in the the rest of the cheese until melted.
Step #21 (Now cook pasta if using fresh ones).
Step #22 Add a little, less that 1/4 c, of the cooking water from the pasta to the sauce & stir.
Step #23 Pour sauce into serving container, cover & set aside.
Step #24 In a large serving bowl mix cooked Tortellini & beans, serve as soon as possible with sauce on the side.