Make the Pesto:
In a food processor, mince the garlic. Add the arugula and hazelnuts and process until it is a fine paste.
Add the Meyer lemon zest and juice and combine.
With motor running, slowly add the olive oil.
Add the grated cheese and mix briefly. Set aside.
Fill a 6 quart or larger pot with water and bring to a boil. Keep hot.
Break the tough ends off each asparagus spear and throw away. Cut the spears into 1" diagonal pieces.
Cut the bacon strips crosswise into 1/4" wide slices.
In a sauté pan, heat 1 tbsp. olive oil. Add the bacon and cook over medium heat until almost crispy. Remove to a plate.
Add the asparagus pieces to the pan and cook until almost done, but still a little crunchy. Turn the heat off.
When the pasta water is boiling add a tsp. of salt and the pasta. Cook until al dente.
Drain the pasta in a colander reserving 1 cup pasta water. Return the pasta to the pan.
Turn the heat back on under the asparagus to warm.
Over low heat, add 2 tbsp. butter and 3/4 cup of the pesto. Stir gently to combine. Add about 1/2 cup pasta cooking water. The sauce should start to be creamy. Add a little more until you have the right amount of sauce. Keep warm.
When asparagus is warmed through, platter the pasta in a dish and top with the asparagus. Finish with some grated Pecorino on top.