Heat butter and olive oil in a large sauce pan over medium. Add onion and cook 4-5 minutes or until translucent. Add garlic and cook for 1 additional minute. Add crushed tomatoes and basil and bring to a simmer. Season with salt and pepper.

Cook for 20 minutes and then add spinach. Cook for an additional 5 minutes and then pour in milk and stir to combine.

Bring a large pot of salted water to a boil over high heat.

Whisk together ricotta, Parmesan, eggs and salt in a large mixing bowl. Add the flour and mix with a rubber spatula until just combined. The mixture should be slightly sticky. If too sticky, add another tablespoon of flour.

Shape the dough into a round disk and divide into four even pieces.

On a lightly floured work surface, roll each piece of dough into a 3/4 inch thick log. Cut each log into 3/4 inch pieces. Lightly flour the gnocchi pieces and toss to prevent from sticking.

Add the gnocchi to the boiling water. Once they rise to the surface, cook for 1 minute. Remove with a slotted spoon, drain well and toss with creamy tomato sauce. Sprinkle with Parmesan cheese and serve immediately.