Mix the dry ingredients: In a large bowl, whisk together flour, sugar, instant yeast, and salt until evenly combined.
Combine the wet ingredients: In a separate bowl, whisk the warm milk, warm water, egg, melted butter, and vanilla.
The liquids should be warm, not hot, to avoid harming the yeast.
Make the dough: Pour the wet mixture into the dry ingredients. Stir with a wooden spoon until a shaggy dough forms. Turn onto a lightly floured surface and knead for 5–7 minutes until smooth and slightly springy.
If the dough is very sticky, dust with a little extra flour, but keep it soft.
First rise: Place the dough in a lightly greased bowl, cover, and let it rise in a warm spot for about 60–75 minutes, or until doubled in size.
Roll and cut: Punch down the dough and roll it out on a lightly floured surface to about 1/2 inch thickness. Use a heart-shaped cookie cutter (about 2.5–3 inches wide) to cut as many hearts as you can. Gather scraps, re-roll once, and cut more.
If you want a “ring” style, use a small cutter to remove a mini heart from the center.
Second rise: Arrange the hearts on parchment-lined trays, leaving space between each. Cover lightly with a clean towel and let rise 20–30 minutes, just until puffy.
Preheat the air fryer: Set your air fryer to 350°F (175°C) for 3–5 minutes. Lightly spray the basket with oil.
Avoid heavy coating; a thin mist helps browning and prevents sticking.
Air fry in batches: Place a few donuts in the basket without crowding. Lightly mist the tops with oil. Air fry 4–6 minutes, flipping halfway, until golden and cooked through.
Time may vary by model; check at 4 minutes to avoid over-browning.
Make the glaze: While the donuts cook, whisk powdered sugar, milk, vanilla, and a pinch of salt until smooth and pourable. Adjust with more milk to thin or powdered sugar to thicken. Add food coloring if desired.
Glaze and decorate: Cool donuts for 5 minutes so the glaze sets nicely.
Dip the tops into the glaze, let excess drip off, then place on a rack. Add sprinkles or strawberry dust right away. For extra shine, double-dip after the first layer sets.
Serve warm: These are best within an hour of glazing, when the texture is soft and the glaze is just set.
