Step 1
Pour water into the pot of a multi-functional pressure cooker (such as Instant Pot®) and place a steamer basket inside. Place butternut squash and potatoes in the steamer basket. Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 5 minutes. Allow 15 minutes for pressure to build.
Step 2
Release pressure carefully using the quick-release method according to manufacturer's instructions about 5 minutes. Unlock and remove the lid. Use a pot holder to remove the steamer basket and set aside to allow the squash and potatoes to cool slightly about 5 minutes.
Step 3
Press the squash and potatoes through a ricer into a large bowl. Add egg and salt and mix thoroughly. Sift about 1 1/2 cups of flour over the mixture and mix to combine. If the mixture is still sticky add a bit more flour until it comes together. Turn out mixture onto a well-floured surface and knead slightly adding more flour until the dough is no longer sticking to your hands or to the surface.
Step 4
Divide dough into 4 parts. Line 2 baking sheets with parchment paper and dust with flour.
Step 5
Take 1 piece of dough and roll it into a 1/2-inch thick rope on the floured surface. Cut the rope lengthwise into 1/2-inch pieces. Working with 1 piece at a time roll each piece down a floured gnocchi board to make ridges. Transfer gnocchi onto the prepared baking sheet. Repeat with remaining dough. Place baking sheets in the freezer while you prepare the sauce and spinach.
Step 6
Bring a large pot of salted water to a boil.
Step 7
Meanwhile place wet spinach in a large skillet over medium heat. Cover and allow condensation to build until the spinach starts to wilt about 3 minutes. Remove lid and stir the spinach until wilted and the pan begins to dry. Divide spinach among 4 serving plates.
Step 8
Combine butter and olive oil in the same skillet that you cooked the spinach. Heat over medium-high heat until mixture begins to foam. Add sage garlic and red pepper and swirl the pan to combine. Remove from heat.
Step 9
Cook gnocchi in boiling water until they float 3 to 4 minutes per batch. Remove with a slotted spoon and transfer to the skillet with the garlic-sage butter. Toss lightly to coat. Place gnocchi on top of spinach on the serving plates and sprinkle each with 1 tablespoon Parmigiano-Reggiano cheese. Serve immediately.