Place 180 g whole-milk ricotta in a fine-mesh sieve set over a bowl. Let it drain for 20 minutes to remove excess moisture.
In a large bowl, whisk together the dry ingredients: 140 g all-purpose flour, 40 g rye flour, 1 tbsp coconut sugar, ½ teaspoon kosher salt, and ½ teaspoon ground cardamom. Add 130 g cold unsalted butter, cut into small cubes.
Work the butter into the flour with a pastry cutter or your fingertips until the mixture forms coarse crumbs with a few pea-sized pieces. Add 1 teaspoon lemon juice and 4-5 tablespoons ice water. Stir gently until the dough just comes together. Add the fifth tablespoon of ice water only if the dough still seems dry. Shape into a disk, wrap tightly in plastic wrap, and refrigerate for at least 1 hour. I also like to roll it lightly and store it like this.
Combine the drained ricotta, 50 g cream cheese, 1 egg yolk, 11½ tablespoons honey, 2 teaspoons lemon zest, ½ teaspoon vanilla, and a Pinch kosher salt. Mix until smooth. Refrigerate until ready to use.
In a separate bowl, gently toss 400 g fresh blueberries with 1 tablespoon honey, 2 teaspoons cornstarch, 2 teaspoons lemon juice, 1 teaspoon lemon zest, and ¼ teaspoon kosher salt until evenly coated.
Preheat the oven to 400°F (200°C). Line a large baking sheet with parchment paper.
On a lightly floured surface (or directly on the parchment paper), roll the chilled dough into a rough 12-inch circle about ⅛ inch thick. Transfer it to the prepared baking sheet.
Spread the ricotta filling in an even layer over the center of the dough, leaving about a 2-inch border around the edges. Spoon the blueberry mixture evenly over the top of the filling. Fold the edges of the dough over the filling, pleating as you go to create a rustic border. If you like, scatter a few extra fresh blueberries over the top.
Refrigerate for 15 minutes to firm the butter before baking.
Brush the entire crust with the 1 beaten egg, and sprinkle evenly with 1 tablespoon turbinado sugar.
Bake for 40 to 45 minutes, until the galette crust is deep golden brown, the blueberries are bubbling, and the ricotta filling is just set. If the crust browns too quickly, tent loosely with foil during the last 10 minutes.
Place 2 tablespoons butter in a small saucepan over medium heat. Cook, swirling occasionally, until the butter foams and the milk solids turn golden brown. Stir in 1 tablespoon honey Set aside.
Let the galette cool on the baking sheet for 20 minutes. Brush the warm crust generously with the honey-brown butter glaze, then brush a small amount over a few blueberries for a glossy finish. Serve warm or at room temperature with whipped cream, crème fraîche, or a scoop of ice cream
Notes
Drain the ricotta - we don't want soggy bottoms.Keep the butter cold all the way through. Cold butter is what creates the flaky pie crust texture. Chill the assembled galette before baking.