Heat 2 tablespoons canola or grapeseed oil in a large cast iron skillet or large Dutch oven over medium heat. Melt the butter, and once melted, add the onions. Stir and cook for five minutes and then reduce the heat to low. Add ½ teaspoon salt and ½ teaspoon black pepper and continue cooking for 45 minutes to 1 hour, until deeply caramelized, stirring occasionally. Remove from the heat and let cool completely.
Preheat the oven to 425°F. Line a half sheet-pan with parchment paper.
Lightly flour a work surface area. Unfold the puff pastry and roll into a rectangle. Use a paring knife to score a 1-inch border around the edges, being careful not to pierce all the way through. Using the same knife or a fork, poke holes throughout the center of the tart all over. This helps prevent bubbling while baking. Refrigerate tart for 30 minutes.
Evenly spread ricotta cheese over the dough, leaving a 1” border. Season with ¼ teaspoon salt and ¼ teaspoon black pepper, top with the caramelized onions, then place the pear slices over the onions. Drizzle pears with ½ tablespoon olive oil and season with remaining ¼ teaspoon salt and ¼ teaspoon black pepper. Sprinkle blue cheese over the pears. Combine the egg yolk and cream in a small bowl. Brush egg wash onto the border of dough and sprinkle with anise seeds, if using. Bake the tart for 30 minutes.
Meanwhile, in a small skillet, heat 3 tablespoons of canola or grapeseed oil. Add the sage and fry for 30 seconds. Remove sage leaves and drain on paper towel. Set aside until ready to garnish tart.
Remove the tart from the oven and drizzle with 2 tablespoons of honey and place back in the oven for 5 minutes.
Transfer the tart to a cutting board. Let cool for a minute or so. Top with the slices of prosciutto, pecans, and crispy sage. Cut into pieces and serve immediately. Enjoy!
