En doesn't answer the door.
This is odd, since Atsushi still has the message telling him to come over open on his phone and especially because he's been waiting by the door for nearly five minutes now, knocking with less and less polite care as the time passes. He can hear something inside, the whir of something electric running and the occasional clatter of metal; it's a little worrying, given En's usual penchant for staying in bed or sprawled on the couch as much as humanly possible, unsettling enough that Atsushi is sincerely considering the likelihood that a stranger has broken into En's house and is using the opportunity to run several small appliances. Then there's a crash, a yelp of a curse that carries clearly through the door, and Atsushi is lurching forward to reach for the handle on a reflex that doesn't bother waiting for a decision.
"En-chan?" he calls as the door comes open, as he stumbles into the entryway in the first immediate rush of concern. The air is warm, humid with a sweet smell Atsushi can't place but that doesn't seem immediately threatening. "En-chan, are you okay?"
"Atsushi," En says from down the hall, voice strained on something Atsushi doesn't recognize, and Atsushi's kicking his shoes free as fast as he can, moving down the hallway almost before he's left them in the entrance. His heart is pounding, frantic with concern for a possibility he can't even form in his head, and then En comes swinging around the corner so fast Atsushi runs right into the hands the other has thrown out to stop him.
"Stop," En says, mouth approximately on level with Atsushi's forehead so the word ruffles against dark hair. "I'm not ready."
"What?" Atsushi asks, derailed into a moment of distraction; then, catching up with his own adrenaline: "Are you okay? I heard you yell and I-"
"I'm fine," En says, rushing over the words and taking a step in to push Atsushi back down the hall. His hands are warm against Atsushi's shoulders, his fingers catching oddly against the other's shirt. "Just wait for another few minutes."
"You told me to come over," Atsushi says, truly confused now as he takes another unwilling step back down the hall. "What's going on?" He takes a breath, squints against the haunting familiarity of the scent in the air. "Is that cake?"
"Ah," En says, and stops trying to push Atsushi back out the door.
"Are you cooking?" Atsushi asks. When he blinks he can bring his focus away from the carefully blank expression on En's face and down to his shirt and the faint dusting of white dampening the color of it into something far more faded than it is in truth. There's something smeared up En's arm to make a line just against the outside of his elbow, and now that Atsushi really looks he can see the marks of fingers shoved through gold hair to knock it haphazard around the other's face.
"I was trying to make your birthday present," En says, his hold easing on Atsushi's shoulders as some of the unusual stress of secrecy fades from his expression. "The recipe didn't say it would take so long."
"Is that batter?" Atsushi asks, still stuck on the spill marking a pale pattern against En's arm. When he reaches out it catches sticky on his skin, clings to his fingertips and drags sweet over his tongue when he lifts his hand to his mouth.
"The kitchen is a mess," En admits without any visible sign of apology. "I was going to clean up before you got here but I lost track of time."
"Oh god," Atsushi says, shocked into horror at the first mental image of the mess waiting around the corner. "How bad is it?"
"It's alright," En equivocates. "I think the oven is almost ready, finally."
"Show me," Atsushi says, and En does, leads the way around the corner and into a kitchen that is really only about half as disastrous as Atsushi was braced for. There's a spill of sugar across the counter, white dusting the surface like snow, but the bowl of cake batter is set aside next to an empty pan, the oven radiating warmth that promises baking soon.
"Okay," Atsushi says, considering the current situation as the oven reaches the preset temperature and clicks itself off. "We can handle this." He straightens his glasses, looks around to find a sponge to start wiping the mess up off the counter; the water runs warm over his fingers, washes away the last clinging sticky-sweet of the batter he wiped off En's arm.
An arm winds around Atsushi's waist, En's face settling at his shoulder to pin him still as he squeezes the sponge to mostly-dry. "Sorry," En says, voice low and soft on sincerity. "It was supposed to be ready when you got here."
Atsushi leans back, presses his weight in against the support of En's chest; when he turns his head sideways En tips in to meet him, his mouth catching and dragging at the corner of Atsushi's lips.
"It's okay," Atsushi says, a little soft because he doesn't mind and a little hot because En's humming against his mouth, shifting to get closer from the awkward angle they are at. "I like cooking with you."
"Yeah," En agrees, and Atsushi abandons the sponge to turn around completely, sliding against En's gentle hold so the other can lean in and push him against the edge of the sink, so Atsushi can turn his head up and shift the delicate drag of En's lips on his into something a little more like a proper kiss.
"Should we start the cake?" En asks some time later, when Atsushi has forgotten about the mess and the cake and his surroundings entirely for the way En's slightly sticky fingers curl at the back of his neck and the way En's knee fits between his.
"Oh," Atsushi says, blinking himself back into the present and considering the kitchen. "Yeah, I guess we should."
It takes fifteen minutes - too long - to get the kitchen reasonably tidy again and to decant the batter into the pan and into the oven. Luckily the cake is supposed to be left to bake for another twenty minutes, and since they have to wait already Atsushi has no complaints at all about retreating to En's room - and En's bed - to pass the time before the cake is ready.
As far as birthday presents go, he's decided this is the best he's had even before the very-slightly-burned cake is ready to eat.